Some wood has stress that makes the kerf close and pinch the blade or open and push against the blade (it doesn't take a lot of pressure to flex a riving knife). What to do?
Get different wood, Sure, we're all going to do that....
Rip on a band saw, safer but the problem is similar
Install a half fence that goes just past the blade
Don't cut all the way thru and finish with a hand saw
Other?