It does sound a rather nasty turn. I'd think there should be grandfathering, but I'm not familiar with the American PT system. If it is so, you may have the exam loophole.
I'd always heard that if we in Canada wanted to work in the states we had to do the US written and practical physical therapy exams, the NPTE, to be able to. But also, each state had different requirements, so it's not a general sweeping statement. If you wanted to work in Canada, you'd have to do our written and practical exams, as well.
Now, I'm not sure if we now would be denied as well...I'd have to look at that list of CAPTE approved schools.