pfs4 could happen if the sources would have been open.
In theory I suppose that could happen...
for instance i have formatted an pfs3 partition using normal format command. there were muforce hits and the task froze. nevertheless rhe partition seems to be formatted allright. checked that few times and im using it ever since with no issues. one could cure issues like thiese perhaps.
If it is indeed an issue, sure. Were you able to reproduce these hits on further testing?