Good day to all and Happy Holidays. I have a Bronica SQ-Ai with 120 film backs that seem to stop advancing around the 8-9 mark on the counter. It will shoot fine and advance 1-8 and then I feel like I am double exposing the 8-9 frame. I try to advance the film but seemingly no movement. I'll even use the film back advance but again, its seems that the film is not moving. I have been researching a lot online, here, Flickr and other spots but I am not having much luck in trying to troubleshoot my problem. If anyone can share some tips on how you were able to correct a similar issue, please let me know. Thank you for your time.

God Bless,
David