Filing this issue off of the review feedback from @ericsnowcurrently on this PR here:
#13667

I'm actually leaving that PR parked for the moment as I agree with the comments on a consistent approach needed for this. My fix might have solved things for one customer, but I'm less confidant that those are the right fixes and would work with all scenarios.

Currently from ones that I know about there are two open customer issues related to this:
https://github.com/microsoft/vscode-python/issues/13640
and
https://github.com/microsoft/vscode-python/issues/13493

In the second of those issues my fixes did resolve the issue for the customer. But only with the changes in both execModule and shell_exec.