Hi Adam ...
.... that's normally a sign that the guitar tech didn't drill the correct sized pilot hole for the strap button screw which is the MOST important part of the operation.
If it's just a crack and nothing has broken off then there's nothing really to worry about, infact even if the end of the heel did break off it'll probably still not affect the guitar much, just look bad.
Solution if it's only got fine a stress crack
- get some good wood glue in there and compress/clamp it, leave overnight / 24hrs to harden then re-drill with the CORRECT drill bit and try again slowly and carefully.
If clamped correctly with the right pressure, a good wood glue will impregnate the wood fibres and be incredibly strong.
Hope this helps and let us know how you get on.