As a work-around ... pivot the fabric and sew forwards all the time.

QUICK DIAGNOSTIC:

What happens if you manually rotate the wheel backwards? If it stitches OK, the problem is not in the timing, it's in the reversing button and what it does to the drive components.

If it doesn't stitch OK, it's happening at the bobbin hook and the feed area.

As a longer-term project:
1 - take apart and clean the bobbin and feed dog components
2 - clean the entire chain of things between the reverse button and the bobbin and needle. (something may be keeping it from engaging correctly)

Last resort:
3- have the timing adjusted (It