Confirmed - cause found, patch not written yet.

Two floors from different layers sit at exactly the same place, so the game reads you as being on the wrong layer and lifts the scenery in front of you.

Moving it out of OPEN so the list reflects reality: this one is pinned down to exact files and lines, so what is left is writing and testing the change, not working out what is wrong.

Fixed - commit 1295e326, in the next build.

On that map two pieces of floor from different layers sit at EXACTLY the same height in the same place (x 391-419). The game picked the wrong one, decided you were on layer 1, and lifted all 11 layer-3 objects in front of you - Lara included.

The fix prefers the floor that is joined to its neighbours, which is the one you are really walking along. That resolves 52 of these overlaps across 22 maps.

Deliberately NOT changed: where BOTH overlapping floors are joined up, the existing behaviour stays. That would affect 283 more spots across 79 maps, and no original-game source says which of the two you should be standing on - so changing it would mean inventing the answer.