gdebi is a universe package, and hence the responsibility of its maintainers and/or the maintainers of the affected flavors at first hand.
You talk about “the bug in VTE”. A more fair description of the situation is this:
gdebi-gtk which is broken in Ubuntu (but not in Debian for some reason, so it’s not crystal clear where the root cause lies), and in this very old bug report VTE upstream claims that there is no issue with VTE. Nevertheless, Ubuntu carries a patch in VTE to work around the
gdebi-gtk problem, but some upstream code reorganization in VTE has made the patch no longer effective in 21.10.
Not sure why you post about it here. You submitted the bug, and it’s being discussed there.