@britzl downloaded 1.2.147 and reproduced my issue in post #6.
Post #6 highlights a more subtle issue and may need a new DEF- bug.
It refers to using a tilemap already instantiated in the main collection, and calling set_tile() to replace a collision mask tile with non-collision mask tile.
The collision mask does update, but the existing contact point normal vectors persist until the colliding object has been moved away.
i.e., set_tile() does not remove physics contact points.
I suspect the same bug may apply to factory-spawned tilemaps.