> To test without openblas , you can renable netlib blas
> $ mv /usr/bin/cygblas-0.dll  /usr/bin/cygblas-0.dll_bk

Yep, works fine with netlib blas. Pure C repro case is attached,
gcc -g 5728.c -o 5728 -llapack && gdb ./5728

I can submit upstream, unless you'd like to.

-Tony