While trying to run certain tests we found that the test run would just sit and spin with no output (log/screen or otherwise). Finally found a correlation between the cmd line flag “unattended” and the source flag “EAutomationTestFlags::RequiresUser”. Removing the cmd line flag fixed the issue. Tests proceed and complete.
I can’t say that this is bug but it is certainly a weird interaction. Posting in case someone else runs across this or knows something about it.