Paulo,
I apologize for taking so long to get back on this.
I didn’t use your approach because I was using the pre-built Vtk module for MSYS2 and installed with pacman.
What I discovered in the mean time is that my error occurs if I set -g or -O0 on the compiler flags. If I set -O1, -O2, or -O3, I compile my code just fine and don’t see the problem.
To me, this does appear as a compiler bug (or what ever one wants to call it). At least I have something that works.
Thanks for all who responded.
BK