Cannot remove zfs empty directory

[Ali Abdallah]

Hello,

I'm having a strange issue deleting an empty folder on the zfs
dataset zroot/usr/home

$ cd $HOME/.cache/chromium/Default
$ ls -la
drwx------  3 ali  ali  3 Nov  6 14:40 ./
drwx------  3 ali  ali  3 Nov  6 14:33 ../
drwxr-xr-x  2 ali  ali  4 Oct 19 11:30 cache/
$ rm -rf cache
rm: cache/: Directory not empty

$ ls -ld cache
drwxr-xr-x  2 ali  ali  4 Oct 19 11:30 cache/

the size is 4, which is strange since the directory looks totally empty.

ls -la cache/
drwxr-xr-x  2 ali  ali  4 Oct 19 11:30 ./
drwx------  3 ali  ali  3 Nov  6 14:40 ..

I don't have chromium since long time, originally the machine was
running FreeBSD 12.1 (now running FreeBSD 12.2), but the issue was
present before the upgrade.

zpool status -v gives not errors at all.

It is not a big deal, but just trying to understand what is happening
here.

Regards,
Ali