EDIT
I waited another day after the nether portal had been moved, and it seems this issue has been fixed. However, I still receive the "Global resources reset" message upon opening the game
I've been having this same issue. I thought originally my issue was that I had just exited a nether portal, (bug MCPE-44815)
I have tried the workaround from the other bug, and I am still getting the "Building terrain" constantly.
EDIT
I waited another day after the nether portal had been moved, and it seems this issue has been fixed. However, I still receive the "Global resources reset" message upon opening the game