Mind you this is not a major bug, but it nearly ruined my optional for “don’t allow a colossus to die”. If you have Grizzlies on the field (using Grizzly battalion) and also have a colossus, the game will only recognize the Grizzly visually as selected units, this affects gameplay however because if you have the Grizzlies and Colossus selected at the same time, you can’t command them separately because the game thinks the Colossus is a Grizzly probably due to it replacing Grizzly in the heavy vehicle slot. So if you have both selected, and then command what looks like the Grizzlies (in the selected units bar) to…attack a grunt squad, both the Grizzlies AND Colossus will attack, whether or not it’s a basic attack or ability. This shouldn’t be too much of a worry with good micro but if you’re a scrub (like me) then this can make or break your Colossus’s day.
My case: I selected all units then scrolled to Grizzly to fire the missile barrage at a large group surrounding the Hunter Captain, but then along with the Grizzlies, came the Colossus trying to stomp its way over there lol