Sorry, late to the party as usual but some thoughts.

Easy enough to check if you are dumb thumbing the stick. Plane on a table where you can watch the control surfaces as you operate the tx. See if in fact you or the tx itself are moving the ailerons when pulling elevator.


But probably most likely is your repower in action. It's now faster. It will require less control throw to operate it. Simple physics, slow speed will require a large throw to get a quick response.
At high speed it take very little to get a response. It may be that you are just adding too much throw now then the plane needs.

Also a very common problem when say attempting a loop, is to use too much elevator. It will cause a plane to snap/roll out of the loop. Simply easing off the elevator will eliminate this.