I know of two instances, but they were short lived. One revolved around hole_birth, and the other around reflinks and sendfile... but that second one could ha

I know of two instances, but they were short lived. One revolved around hole_birth, and the other around reflinks and sendfile... but that second one could have been a python/portage issue instead. There was one instance of issues with encryption, but the feature was in testing at the time, and has long since been rectified. As for failure modes... the first issue above caused issues with send/receive, the second issue caused empty/sparse files to be written instead of data, and the encryption issue caused issues with send/receive and/or garbage data.