Onyxia Buff not dropping on all layers on Dreamscythe [Anniversary Realm]?

Rallying Cry of the Dragonslayer buff is not dropping across all layers for the Alliance on Dreamscythe. Has this changed recently?

I experienced this on nightslayer once. Ony dropped and my layer did not get it. I think its got to do with a new layer opening at the time of the drop or something.