Okay. I restored the .h file and kept the mod in the cpp file. I tried building with that setup.

Results were the same --- a failed build after about 20 minutes. I don't know if that result will change by moving to a virtual machine environment with 3.5.10 not installed.

I will try that next!

I'll keep testing as my schedule allows the next few days but I know I won't be able to provide much attention thereafter for a few weeks. I should be able to putter and tinker a little bit during that time, so any bugs we resolve now will help much the next few weeks.