They think they have seen your issue but no reply, because they're fixing it right now. They're only reply to issues which are duplicates or else.
I'm not sure though, but it's sure laggy when flying in creative mode, even if the world's size is small, right? So let's just say this issue have something to with loading chunks... I'm not so sure myself.
I think maybe your world just have capped the limit, 94.6mb, max size of a world.
yeah... Now you mentioned it. they're actually really rare. Haven't seen any of them for awhile.
Nah ~ Not gonna. There're issues with that achievement already (MCPE-17233), and maybe the problem is about XBox account. Sometimes when you logging in, you get your achievements, sometimes you can't.
"Map Room" achievement is also broken,too!
Still an issue in 1.0.0 and when you move your cam while fishing, the line is not attached to the bobber.
Sorry, in 1.0.0 on Window 10, horse still follow you when you're holding bread, wheat,... I think the issue still going on.
Update: Win 10 edition, 1.0.0, still have this issue.