md5 not equal

[kkk123dm]

1、 sudo fuse-nfs -c -S -D -L /home/fuse.log -n nfs://192.12.3.6/data -m /abc/1 -o uid=$(id -u),gid=$(id -g),proto=tcp,timeo=120,retrans=3;
2、 cp /data/1.txt(10M) /abc/1
3、 the last ,md5sum these files .but md5 values of these two files are not equal;

i have debug,it is ok
[NFS] 17:09:34 fuse_nfs_open entered [/abc/1/1.txt]
[NFS] 17:09:34 open_cb status:0
[NFS] 17:09:34 fuse_nfs_read entered [/abc/1/1.txt]
[NFS] 17:09:15 fuse_nfs_write entered [/abc/1/1.txt]

What is the reason for the inconsistency in CP MD5 and how can I resolve it?
thanks all answered