Hello everybody, in the thread on the ubuntu tracker someone else pointed out that this was also observed on fedora 26, see comment 14 in https://bugzilla.redhat.com/show_bug.cgi?id=1552037
Apparently it was suggested there (comment 14) that forcing NFS vers=4.0 for the mount appears to fix this as far as it can be reliably reproduced. Note that debian 9 and ubuntu 18.04 apparently default to vers=4.2. I will try that next. Best Regards Christof
