This seems new in trunk. As in "wasn't happening a couple of weeks ago". Its surfacing in the S3A committer tests which are trying to create MiniYarnClusters: all such tests are failing as the mini yarn cluster won't come up with an NPE in FileSystemNodeAttributeStore.recover
I'm not sure why node labels are needed on test clusters; the default implies they should be off anyway.
At the same time, I can't seem to find one specific change in the git log to say "this is causing the problem".