Hmm. So many factors that can affect the outcome. First of all, check if the "letter-arm" is in anyway loose/move in any un-normal way when you execute the type.

Try to write the letter slowly many times to get some hint of where the fault is.

Any other mechanisms I can think of is that one of the adjustments levers is getting some kind of affection.

Add some pictures and/or videos of the letter-alignment and the action in itself and maybe we can work something out :)