EDIT: dev confirmed it's a bug with the current version. It has been fixed internally and will be fixed in the next update.

So a few days ago, I started the game and noticed that the InvisiSuit invisibility broke as soon as I moved.

I don't know if this is a bug (changelog implies that stealth was modified) or an intended nerf (to bring the outfit in line with the other two, which is to say practically useless).

Any word on that?

I'll have to check this out. You should remain clocked as long as you don't:

* Pick up an item
* Interact with something (like an elevator switch)
* Enter an area that triggers a loading screen
* Pick a lock
* Open a side door
* Land an attack on an enemy
* Perform a takedown
* Shoot

... but ordinary movement should be fine.

Of course, you need to make sure that it's activated properly. To activate it, stand (don't crouch) perfectly still in a spot with no security devices or personnel around, and no alarms going off, for five to six seconds.