diff --git a/app/controllers/AnnotationController.scala b/app/controllers/AnnotationController.scala
index 806ceeba709..093559e5a4d 100755
--- a/app/controllers/AnnotationController.scala
+++ b/app/controllers/AnnotationController.scala
@@ -17,7 +17,7 @@ import models.annotation.AnnotationState.Cancelled
 import models.annotation._
 import models.dataset.{DatasetDAO, DatasetService}
 import models.project.ProjectDAO
-import models.task.TaskDAO
+import models.task.{TaskDAO, TaskService}
 import models.team.{TeamDAO, TeamService}
 import models.user.time._
 import models.user.{User, UserDAO, UserService}
@@ -52,6 +52,7 @@ class AnnotationController @Inject()(
     tracingStoreService: TracingStoreService,
     provider: AnnotationInformationProvider,
     annotationRestrictionDefaults: AnnotationRestrictionDefaults,
+    taskService: TaskService,
     analyticsService: AnalyticsService,
     slackNotificationService: SlackNotificationService,
     mailchimpClient: MailchimpClient,
@@ -158,6 +159,7 @@ class AnnotationController @Inject()(
       _ = logger.info(
         s"Reopening annotation $id, new state will be ${AnnotationState.Active.toString}, access context: ${request.identity.toStringAnonymous}")
       _ <- annotationDAO.updateState(annotation._id, AnnotationState.Active) ?~> "annotation.invalid"
+      _ <- Fox.runOptional(annotation._task)(taskService.clearCompoundCache)
       updatedAnnotation <- provider.provideAnnotation(typ, id, request.identity) ~> NOT_FOUND
       json <- annotationService.publicWrites(updatedAnnotation, Some(request.identity)) ?~> "annotation.write.failed"
     } yield JsonOk(json, Messages("annotation.reopened"))
@@ -298,13 +300,14 @@ class AnnotationController @Inject()(
 
   def cancel(typ: String, id: ObjectId): Action[AnyContent] = sil.SecuredAction.async { implicit request =>
     def tryToCancel(annotation: Annotation) =
-      annotation match {
-        case t if t.typ == AnnotationType.Task =>
+      (annotation._task, annotation.typ) match {
+        case (Some(taskId), AnnotationType.Task) =>
           logger.info(
-            s"Canceling annotation $id, new state will be ${AnnotationState.Cancelled.toString}, access context: ${request.identity.toStringAnonymous}")
-          annotationDAO.updateState(annotation._id, Cancelled).map { _ =>
-            JsonOk(Messages("task.finished"))
-          }
+            s"Canceling task annotation $id, new state will be ${AnnotationState.Cancelled}, access context: ${request.identity.toStringAnonymous}")
+          for {
+            _ <- Fox.runIf(annotation.state == AnnotationState.Finished)(taskService.clearCompoundCache(taskId))
+            _ <- annotationDAO.updateState(annotation._id, Cancelled)
+          } yield JsonOk(Messages("task.finished"))
         case _ =>
           Fox.successful(JsonOk(Messages("annotation.finished")))
       }
diff --git a/app/models/annotation/AnnotationService.scala b/app/models/annotation/AnnotationService.scala
index 54577752334..b8fd30a12ea 100755
--- a/app/models/annotation/AnnotationService.scala
+++ b/app/models/annotation/AnnotationService.scala
@@ -313,6 +313,7 @@ class AnnotationService @Inject()(
       for {
         _ <- annotationDAO.updateModified(annotation._id, Instant.now)
         _ <- annotationDAO.updateState(annotation._id, AnnotationState.Finished)
+        _ <- Fox.runOptional(annotation._task)(taskService.clearCompoundCache)
       } yield {
         if (annotation._task.isEmpty)
           "annotation.finished"
diff --git a/app/models/annotation/AnnotationStore.scala b/app/models/annotation/AnnotationStore.scala
index 617634b1793..3076ffa5a51 100755
--- a/app/models/annotation/AnnotationStore.scala
+++ b/app/models/annotation/AnnotationStore.scala
@@ -25,7 +25,7 @@ class AnnotationStore @Inject()(
 
   private def requestFromCache(id: AnnotationIdentifier): Option[Fox[Annotation]] = {
     val handler = annotationInformationHandlerSelector.informationHandlers(id.annotationType)
-    if (handler.cache) {
+    if (handler.useCache) {
       val cached = getFromCache(id)
       cached
     } else
@@ -37,7 +37,7 @@ class AnnotationStore @Inject()(
     for {
       annotation <- handler.provideAnnotation(id.identifier, user)
     } yield {
-      if (handler.cache) {
+      if (handler.useCache) {
         storeInCache(id, annotation)
       }
       annotation
@@ -60,4 +60,6 @@ class AnnotationStore @Inject()(
       case None             => Empty
     }
   }
+
+  def removeFromCache(id: AnnotationIdentifier): Unit = temporaryAnnotationStore.remove(id.toUniqueString)
 }
diff --git a/app/models/annotation/handler/AnnotationInformationHandler.scala b/app/models/annotation/handler/AnnotationInformationHandler.scala
index 8db66842b47..7e5974d70e0 100755
--- a/app/models/annotation/handler/AnnotationInformationHandler.scala
+++ b/app/models/annotation/handler/AnnotationInformationHandler.scala
@@ -32,7 +32,7 @@ trait AnnotationInformationHandler extends FoxImplicits {
 
   implicit val ec: ExecutionContext
 
-  def cache: Boolean = true
+  def useCache: Boolean = true
 
   def provideAnnotation(identifier: ObjectId, user: Option[User])(implicit ctx: DBAccessContext): Fox[Annotation]
 
diff --git a/app/models/annotation/handler/SavedTracingInformationHandler.scala b/app/models/annotation/handler/SavedTracingInformationHandler.scala
index d7b1f26f363..1bd9b7bfd9a 100755
--- a/app/models/annotation/handler/SavedTracingInformationHandler.scala
+++ b/app/models/annotation/handler/SavedTracingInformationHandler.scala
@@ -24,7 +24,7 @@ class SavedTracingInformationHandler @Inject()(
     with Formatter
     with FoxImplicits {
 
-  override val cache = false
+  override val useCache = false
 
   override def nameForAnnotation(annotation: Annotation)(implicit ctx: DBAccessContext): Fox[String] =
     for {
diff --git a/app/models/task/TaskService.scala b/app/models/task/TaskService.scala
index dcd0d97b4ba..a500d770be3 100644
--- a/app/models/task/TaskService.scala
+++ b/app/models/task/TaskService.scala
@@ -5,7 +5,7 @@ import com.scalableminds.util.objectid.ObjectId
 import com.scalableminds.util.tools.{Fox, FoxImplicits}
 
 import javax.inject.Inject
-import models.annotation.{Annotation, AnnotationDAO, AnnotationType}
+import models.annotation.{Annotation, AnnotationDAO, AnnotationIdentifier, AnnotationStore, AnnotationType}
 import models.dataset.DatasetDAO
 import models.project.ProjectDAO
 import models.team.TeamDAO
@@ -19,10 +19,12 @@ import scala.concurrent.ExecutionContext
 class TaskService @Inject()(conf: WkConf,
                             datasetDAO: DatasetDAO,
                             scriptDAO: ScriptDAO,
+                            annotationStore: AnnotationStore,
                             userService: UserService,
                             annotationDAO: AnnotationDAO,
                             taskTypeDAO: TaskTypeDAO,
                             teamDAO: TeamDAO,
+                            taskDAO: TaskDAO,
                             scriptService: ScriptService,
                             taskTypeService: TaskTypeService,
                             projectDAO: ProjectDAO)(implicit ec: ExecutionContext)
@@ -88,4 +90,11 @@ class TaskService @Inject()(conf: WkConf,
       activeCount <- Fox.fromFuture(annotationDAO.countActiveByTask(task._id, AnnotationType.Task).getOrElse(0))
     } yield TaskStatus(task.pendingInstances, activeCount, task.totalInstances - (activeCount + task.pendingInstances))
 
+  def clearCompoundCache(taskId: ObjectId): Fox[Unit] =
+    for {
+      task <- taskDAO.findOne(taskId)(GlobalAccessContext)
+      _ = annotationStore.removeFromCache(AnnotationIdentifier(AnnotationType.CompoundTask, task._id))
+      _ = annotationStore.removeFromCache(AnnotationIdentifier(AnnotationType.CompoundProject, task._project))
+      _ = annotationStore.removeFromCache(AnnotationIdentifier(AnnotationType.CompoundTaskType, task._taskType))
+    } yield ()
 }
diff --git a/unreleased_changes/8756.md b/unreleased_changes/8756.md
new file mode 100644
index 00000000000..98f24e7437d
--- /dev/null
+++ b/unreleased_changes/8756.md
@@ -0,0 +1,2 @@
+### Fixed
+- Fixed that compound (merged) views of tasks, projects and task types would sometimes show outdated annotation data, leaving out the data from recently finished tasks annotations.