I learned on an old 20 with a terrible seat. I duct taped some foam to it. The foam shifted a bit, but I didn't bother to fix it, because I had ordered a KH 24. So when I got the 24 it was terrible ! Pulled to the right like it was bent. Yet careful exam showed the KH was fine. I used to be able to turn left easy and right not so good. Once I got used to the KH I could turn right easy and not left. So have you checked your old uni ? If you learn on a bent one, straight ones will feel weird ! In any event, this problem went away in a few days.
I had a similar probably, leading with the left shoulder and having my upper body twisted to the right to compensate. My seat was straight. I solved it by twisting my seat to the left. It made a massive difference to my riding, speed especially.
