Doesn't make sense if really the exact same size. If exact same size and you don't change rims or suspension, then the new tires also should clear like before! If you said that before was 2 finger gap and now only 1 finger gap, I think the tire size is different than before, meaning now is bigger tires.

The only other possible explanation (but also remote) is that your spring is already sagging, or sitting/relying on the bump stopper to stop/reduce the spring play and now your bump stopper is already worn out hence your car bounces more, rubbing the tires. But again that is also a bit far fetched theory. I still suspect you got the wrong tire size.

It is real but will only happen after pretty long period, even for cheaper brands. Furthermore he said it happened after he changed tires of the same size. Spring sagging happens gradually, not immediately like that after changing tires, so that's why I said it's still far fetched/strange.