Sorry , I have just realised that I have missed some vital information:
I use a blanket on a bending form and, when required, I retouch the side by means of a bending iron using a stainless support strap.
This crack has shown-up out just out of the bending form.
In the past (few) cases bending cutaways I actually had no problems except for some pressure marks on the inside of the bends, that have been easy to repair.
I was thinking about preparing full depth inner and outer forms and use some 30min clear epoxy with strong clamping.
If it solves the problem I can then use the same epoxy as pore filler on both sides and back before starting the finishing process thus to match the final colour tone.
If it doesn't solve the problem then I will just procure another maple set and try one more time
Many thanks for the prompt answers/suggestions received till now, I am new in this forum and very impressed with the technical topics being discussed. I will definitely contribute as much as my modest experience allows

cheers