Agree with Pappy completely. Can't see that heating the bow had any effect on the separation. I've got a similar situation on the lever fade of a molly I built last winter. I didn't wrap it with sinew so that I could watch it to see if it got worse. Added a little CA glue and finished it. No change at all since I first spotted it. Yes it was being heated as I bent it backwards to add a little reflex, but it was the bending, not the heating that caused it IMO. My guess, your good.
