There are earlier reports for exactly this behavior with Bergamot:
In one those threads someone noted: “Bergamot glitched out today. It’s not just bergamot I think, it’s all the flower bots. It will just continue passing, and then resign.”
However, I checked agapanthus and bergamot just now and they look fine. Speculating: If all OGS / flower bots occasionally do it, it may have to do with the server+bot not being able to play a move in time, and then defaulting to a pass.