Nuki Fob 2: "Unknown error 0xFE" in Activity Log after opening door

Hello. I am a new Smart Lock 4 Pro user (so far, so good :slightly_smiling_face:). I also bought one Fob 2, and whenever it is used for opening (unlock+unlatch) the door, an error message is logged (the door gets opened):

As it can be seen, locking the door with the same fob does not log any error.

The Smart Lock 4 Pro is using firmware 4.2.8, and the fob was automatically updated to 4.10.1 upon pairing.

Any ideas? Should I ignore that error?