I agree with Richard - I've not seen an exception in ntdll that wasn't actually my fault for years and years now ...
It's normally a broken string or a corrupt pointer - the 'works in release' is a very good indicator it's memory related
What you can try to do is enable OS symbols - downloadable from the MS Symbol server - it makes the stack dump considerably more intelligible - somewhere in options/debug
You may have to update some dll's to make it work[
^]