Oh, I talked to the CA. They put my bag in the wardrobe/stowage.
Not sure AY staff would ever move "offending" bag. They will try to solve the problem at hand, which is the bag not yet stowed (ie my bag). Has happened to me many times as I prefer board late and often is seated in bulkhead row. This was however the first time I saw the "bag in J, seat in Y-manoeuvre" on AY.