Ensure you don't have alt, ctrl, shift (or any combination of these) bound in game on the keys which your FTL Assist uses.

Beyond that, you can try to delete the macro and retype it from scratch.
I've had situations where a copy/paste fails to work, but deleting it and re-pasting and it will work fine.
Not sure if there is a temporary bug in the blizzard macro system or what else will explain that.

I could not get the keystrings to work with keyclone, so might not be the best to trouble shoot with you.
However, if it worked properly in all combinations with the original toon, but not with the new toon, then its not the set up of the FTL.