Something I've noticed with this, if it helps, is that don't ever log out in these weird unloaded chunks as this is what causes the "building terrain" indefinitely problem when trying to rejoin. Also with the fixing of these chunks, if everyone in the realm quits and stays out for a few minutes (I usually give about 5-10) for the realm to "turn off" as it does this when nobody is online. Then rejoining after the time period, it should have all these chunks fixed. You can tell that the realm is booting back up after you have waited if it takes a while on the "joining realm" part of the loading (before "loading resource packs"). Hope this helps. (:
This is really disappointing seeing this was created in February. I just ran into this problem now. Hopefully it gets fixed soon. (:
Can confirm, I lost my enchanted bow to this problem as well, shift clicked on the dispenser on the left on accident and bow just gone.
If you take anything from this, it is to always have a fire resistance potion on you. Maybe even two. And also feather falling in case there's no lava. 😛