I recently loaded the save of my challenge, but at the volcano level the entire upper portion had lowered itself by one plate unit, causing none of the lower bricks to load. This happened at two or three different heights on the volcano. This was an absolute pain to patch up, and the challenge itself now needs to be redone due to jump distances changing. Has anyone else had this problem? The brick count is only at 25,000 so that shouldn't be an issue.

Previously, a simple 1x4x5 brick connected the lower bricks to the ceiling of the cave.

As seen in the picture above, many bricks simply loaded in mid-air, while the bricks around them disappeared from the .bls
Also, many of the bricks are now "perma-bricks", in that they cannot be hammered although they are supporting nothing. If you use the wand on these bricks, the entire build collapses. Perhaps "help" to save the old build is now out of the question, but I would like help figuring out why this happened.