There are two problems here:
1) there is a lot of complicated logic in the platform behavior to handle slopes, gravity angles, moving platforms etc. As part of handling this it remembers the object it is currently standing on. This means changing the solidness doesn't immediately take effect until you next jump.
2) your example seems to teleport a large solid object over the player. I'm not sure what you expect the platform behavior to do in response, since it's physically unrealistic. So I don't think any weird behavior doing this should be treated as a bug.
Anyway given both these facts I don't think we'll fix this - it's super complicated code to cover an unrealistic case, and there are workarounds (usually "nudging" the player makes it update the standing-on object again).