I think its the drum the wheel sits on. There are fixes online for drilling holes in the drum where you can see the plastic and re gluing it. But tacx has a 2 year warranty on it. Same thing happened to mine a couple years ago and they sent me a new assembly no problem.
Actually here is a fix without drilling.
Here is a different type of fix
I would definitely look at the 2t. Or even a saris h3 if the price is right. I was burned by a kickr core.
Good luck!