reduced the retract from 1.5mm to 1.0mm. This way I could complete the prints. However, this can't be a permanent solution.
#1 I only have been using 1mm retraction for a very long time with Raise 3D printers. Not because of jams but just that some early testing with the Mosaic palette software way back only worked with a limited retract distance. I never needed to change it after that. That was true for BMG and the mini since I have multiple printers with both solutions. I find no such correlation to a BMG specific issue.
#2 Longer retraction of like 6-10mm OK, could understand jams, 1-2mm shouldn't be causing jams and indicates a hotend issue, not a feeder specific issue.
I think you ran into a coincidence here that you changed the feeder and just happened to have an issue at the same time.
1.5mm should not be causing jams, not in my experience and moving to 1mm fixing it, I would not consider that BMG specific or an indication at all. I would consider that maybe you had some dirt or fiber or burned filament check ball effect in the cone of the nozzle and the only way to remove that is cold pull filament cleanouts, changing the nozzle, or sometimes the classic burnout (high temp method with the nozzle removed).