Nsight CUDA Debugging: breakpoint will not currently be hit

I am running VS 2019 and CUDA Nsight visual studio edition V 2020.3
When I create a new CUDA Runtime project using VS project wizard, I am able to set breakpoints and step into kernel code. Then suddenly it stops working and I lose ability to set breakpoints in kernel code and the breakpoints in kernel code sections show the the breakpoint as white circle with red outline and exclamation point with tooltip “The breakpoint will not currently be hit. No executable code of the debugger’s target code type is associated with this line…”
I changed NOTHING in the project or build configuration. This happens after I close a VS Solution and then reopen the same solution later, with no changes. When I reopen the solution, I just rebuild the code and immediately the breakpoints stop working. The -G switch was set the whole time. Nothing changed.
I have reproduced this problem several times now with new solutions.
To repro:
create a solution and add the default CUDA Runtime project.
build debug and set breakpoints, successfully step into kernel code
save and close solution.
reopen solution and breakpoints stop working and the above error appears

  • NOTE: this does not always happen on first time saving and re-opening the solution. Sometimes it takes 2 or 3 iterations of above for it to suddenly quit.

I have noticed when kernel debugging works, when I launch/start debugging it breaks at the entry to the application int main( ) always, but code does not automatically break at int main( ) when it isn’t working.