If such a well-known bug is still not fixed, then I guess there must be a reason for it, but in case there is none, fixing the invulnerability of players touching the very left side of a level would be nice.

Also, I request a special trigger zone which sets a trigger to 1 when a player is using TSF, also working in SP. Although I don't see much use of it in MP, maybe except some tests including morph levels, which could be skipped if using a wrong version, in SP they can come in handy if some of the levels of a pack are TSF-only (due to the tileset size or features used). With some use of multiple exits feature, this could be made to let 1.23 users play packs with only few TSF levels by either skipping them or playing an alternative version of them.