In Order Too Replicate This Bug you'll Have To get a Uncompressed Behavior Pack & a compressed Behavior pack, Now The Uncompressed Behavior Pack Has to be in the world folder in the behavior_packs folder when attempting to upload the world With the uncompressed Behavior pack, the status bar will say 100/100% out of the upload, but it'll say cancel instead of Let's go, but trying too upload with a compressed behavior pack it will say it uploaded, Let's go,  but here's the strange thing it says it uploaded but when you go & play it's a different behavior pack completely to confirm this, i downloaded a copy of the world with the compressed behavior pack applied, instead of it being "My behavior pack" it was "op & crazy add on" Behavior Pack, **++