From what I have seen on awning arm mis-alignment issues, they are usually caused by one of 2 situations:
• The fabric has moved on the roller tube either forward or back and causes the roller to not hit center when it rolls the fabric.
• The fabric on the awning rail mounted to the sidewall of the trailer has moved and causes the same situation.
The remedy is to remove the retaining screws that should
be found at either end of the fabric on both the roller tube and the awning rail. re-center the fabric on both and re-apply the screws. This will generally solve your problem.
The other cause I have seen is fabric stretch. For whatever reason, the fabric can stretch asymmetrically and will have the same effect. Unfortunately, the remedy to this situation is fabric replacement.