Just for completeness - this was a problem with JPSofts tcc.exe, not with TSE.
sanity1 runs fine with 4.50.16 when not running tcc.
In a future version of the Windows editor, instead of running
processes using the value of the COMSPEC environment variable, I'll
always use cmd.exe, which is a part of Windows, and will always be
there.
Thanks for testing!