I’m no expert because I don’t use a trainer, but I’ve a few mates that do, and have rub into similar issues. So I’ll throw my hat into the ring for heat stress. That seems the most likely, and it can cause a lot of different issues. There’s two main reasons for this: 1. Rollers generate a lot of friction, friction generates a lot of heat. And 2. When you’re on a trainer, there is no wind. Out on the road, the faster you go, the more wind resistance you create. That has a huge cooling effect on your wheels and tires, that simply isn’t there on a trainer. So that heat stress is going to have the biggest impact on whatever the weakest part of your setup happens to be. Could be tires, tubes, spokes, rims, or all of the above at once.
the suggestion of a fan pointed down at the contact point, particularly for your rear wheel, could completely eliminate the problem be reducing the heat build up. That’s what I would recommend first. If that doesn’t do the trick, heavier duty tubes, or trainer specific tires would be my next option. If that doesn’t work, it could be that your rims aren’t playing nice, but that seems unlikely. I’d place all my bets on heat stress. Reduce the heat, problem solved.