In mdcache_readdir_chunked  the directory content trustworthiness needs to be re-evaluated after initially acquiring the lock  (circa lines 2740 and 2744) as well as when the lock is re-acquired (circa lines 2780 and 2984) after dropping it.  Re-evaluating the mde_flags for the directory and calling mdcache_dirent_invalidate_all if the content or dir chunks cannot be trusted seems to fix the issue reported here: https://lists.nfs-ganesha.org/archives/list/devel@lists.nfs-ganesha.org/thread/XAJL7SWXYFTE3WVCUKQAATKNN3XSGTCT/