Looks like this tiny nightmare might be behind me. I don't know what happened, but some combination of git clone, git reset --hard HEAD, git clean -dxff, git checkout master, and manually copying missing admin and cmake .git folders seems to have gotten the switch_all_submodules_to_head_and_clean script to remain calm and quiet and stop terminating.
No more fatal messages.
I updated my wrapper script to tee the output of switch_all_submodules_to_head_and_clean script to a log.
Took 3 hours to clone tde-i18n --- something not right about that.
What a wasted day --- back to building packages and testing!
Darrell