Originally posted by Nobbler:

Originally posted by jonnin:

its from a lack of support and it just takes a while for the game to compute that its not good enough. Adding support below it is the only fix. Often you just need wood iron or iron embedded in the stone to shore it up, invisible and easy to do.

Incorrect. It has support. This is the kind of comment that I designated as try to avoid. Thanks anyway, amigo. I can sit and watch this same block for an eternity, to no change or effect.

However, moving away from it, to the point it despawns, then back towards it? Or - logging out and back in? Sometimes, but not every time, causes the popcorn.

and every time this has happened to me, changes to the support has fixed it. Ive had to do this a good dozen times by now, since I build a lot.

what I believe is happening is that they DO have a bug, and that when you leave and come back it {recreates, recomputes?} the structure and its integrity, and somehow that is done {wrong, out of order, slight roundoff error, other??} so that it is either popping when it should not (most likely!) because of the computational / order/whatever error or (very unlikely) it should have popped to begin with, but didn't.
But I assure you, it is entirely tied to structural support, and it can be fixed, with a great deal of trial and error.