It doesn't matter. Whatever I specify on the CMD command line later shows up as the title when I execute GLOBAL.
View attachment 569
WAD. If the command argument does not end with "tcc.exe" (and yours doesn't), TCC will not switch to the "TCC Prompt" default argument. This is by design, as otherwise if you specified a title when starting TCC (i.e., via sui.lpTitle) it would always be overridden with a default title.
In your failcase, you have to:
1) Start TCC from CMD (an uncommon event)
2) Don't use a fully-expanded filename for TCC (an uncommon event which can only happen when you deliberately do it while starting from CMD)
3) Use TITLEPROMPT (an uncommon event)
4) Set UpdateTitle=No (an uncommon event)
5) Run an internal command like GLOBAL which calls the parser recursively (an uncommon event)
6) Pause the internal command so you can see that the title has momentarily reverted to the original one (an uncommon event)
Add all of those together, and you get a 1-in-15-years issue, which IMO at most falls into the "curious output" category, and is not a bug. Or worth a tiny fraction of the time spent talking about it.
If you have an example of why this causes a real problem for you, please post that instead of this example.