T perm and Y perm AUF problems

[Waffles]

So when I have a U’ AUF on T perm or Y perm (or any algorithm that ends with an F’) I do it with my middle finger. Sometimes the S layer will destabilise and pretty much ruin the solve. I kind of want to know if anyone else has this problem (RS3M 2020) and how to fix it because I ruined a 10.03 with that.

 

[xyzzy]

Nothing wrong with left index F' into left middle U' if you can pull it off accurately, but if you can't, try different fingertricks:

F' with right thumb
U' with left index

or

F' with left index
U' with right index

 

[Cubing Forever]

It happens with any cube, not just the RS3M. A simple fix is to keep the pinky under the S slice.