I can't figure out what key is doing it and I don't know how to check. I do know that sometimes when I'm using the console, I'll accidentally hit a key that both causes that slow-mo and triggers some sort of re-positioning screen to appear where I can move something around the screen, although I've never been able to figure our what. Once the slow-mo is active, there is no way to turn it off. The only way to get rid of it is to reload a save or the game itself. Here are all the mods I'm using:
EDIT:
It happened again, with the repositioning menu appearing. If I try to actually use the buttons on the prompt to move whatever thing it's talking about, it simply closes the box and traps me in slow-mo. I should clarify that this isn't bullet time slow-mo. We're talking 100% unplayable slow-mo. Try to move forward and I don't think you'd see the full action even after five minutes. Here's a screenshot of the console, which shows a small amount of information that could help, specifically the bit about the position and size.