Grasping at straws here, honestly.
Been having a persistent CTD issue in multiplayer environment only when performing a variety of operations on an object, including - but not limited to - SetInvisible, SetScale, SetObjectMaterial, synced network variables, some of which are threaded operations.
Given the difficulty in reproducing the exact conditions which trigger the issue, eliminating potential causes one by one is taking *months*, and it'd be nice to just have a pointer in the right direction if possible.
The crash is persistent, affects all clients within the vicinity of the object, and the crash is triggered immediately upon clients rejoining as well. Initially I suspected a P3D issue but it's been re-made as simplisticly as possible (single cube geometry, and single sphere mesh), so my suspicion is that it's somewhere in one of the transformation natives like SetScale.
Two dump files from the same session attached (first crash, and crash after restart client).