diff --git a/src/spaces/homspace.jl b/src/spaces/homspace.jl
index a6ae2bc1c..bdb534663 100644
--- a/src/spaces/homspace.jl
+++ b/src/spaces/homspace.jl
@@ -313,7 +313,10 @@ end
 
 function _subblock_strides(subsz, sz, str)
     sz_simplify = Strided.StridedViews._simplifydims(sz, str)
-    return Strided.StridedViews._computereshapestrides(subsz, sz_simplify...)
+    strides = Strided.StridedViews._computereshapestrides(subsz, sz_simplify...)
+    isnothing(strides) &&
+        throw(ArgumentError("unexpected error in computing subblock strides"))
+    return strides
 end
 
 function CacheStyle(::typeof(fusionblockstructure), W::HomSpace)
diff --git a/test/runtests.jl b/test/runtests.jl
index 2e716fa18..84b4abd79 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -113,7 +113,7 @@ include("tensors.jl")
 include("diagonal.jl")
 include("planar.jl")
 # TODO: remove once we know AD is slow on macOS CI
-if !(Sys.isapple() && get(ENV, "CI", "false") == "true")
+if !(Sys.isapple() && get(ENV, "CI", "false") == "true") && isempty(VERSION.prerelease)
     include("ad.jl")
 end
 include("bugfixes.jl")