That will happen with a narrow tip contact recurve. I had that happen the other day with sinew backed juniper. 60" long with 5" reflex. 50# @ 28". In my case the low brace saved it from breaking. It still shoots fine. I had just added little horn nocks that increased the recurve just a tiny bit and made this happen. I got home and filed in new nocks 1/2" below and it's back to stable again.
Eric, my most used personal bow has huge cracks like that all up and down the sides. 49" sinew backed juniper 25-26" draw 48#. I have shot it thousands of times over the last 3 or 4 years. I started to see little signs of wood cell breakdown on one section of the limb finally but have never had a problem with these sinew cracks except they are ugly.