I think I’ve figured out how to edit… so one of my two bases vanished while there should have been at least 48 hours left on the timer. The event log (which I am admittedly not expert at interpreting) suggests there might have been an adjustment made to the decay timers that was at the heart of this occurrence. Anybody?
This happened to me 2 months ago…i had 80 to 100 stability on dungeon/yamati foundation/ceiling tile. Hammer said so…and i had a casting table, table, decorations, a couple boxes sitting on that and some how just poofed into thin air. 
i sent a request into funcom, took photos of my event log (literally claiming stability lost) and stability screenshots of the build and i heard ABSOLUTELY nothing back from them. Good thing i lost a bunch of cooked resources like metals and alchemist base and mods from purges. (Insert sarcasm)
I think at this point my cat is more responsible. Lordy.
In your case, sometimes people dont connect their buildings and start a new build (which sometimes creates a new timer) so always best to connect your build then disconnect it to keep the same timer. If you did that and that still happened. Then who knows at this point.