I'd like to be able to disable/enable collision while having player flying.
First TCL command just disables collision, but second TCL call to re-enable collision (after a few frames) immediately warps player to the floor .
I tried fixing player vertical position in the same frame immediately before and/or after TCL (example)

set savedZ to ( player->GetPos Z )player->SetPos Z savedZTCLplayer->SetPos Z savedZ

, but it does not work.
Anybody has a similar problem solved?

I think SetPos does make actors snap to ground every time it's called, except for when the actor has levitation on them. You could try temporarily giving the player an ability with a constant levitation spell effect.

Thanks, but player has already a levitation spell. Problem is the second TCL reenabling collision ignores also levitation effect for that frame, you can test the TCL TCL glitch also from the console when flying.
I think TCL may be hardcoded to reset player position before reapplying any other effect/function/positioning.