The gist of it is, it's a vte issue. Guake seems to encounter them pretty regularly. https://gitlab.gnome.org/GNOME/vte/-/issues/270 The issue seems to be fixed upstream in vte-0.62.1, so could we maybe bump it, or, if that's problematic, pick up the patch from https://gitlab.gnome.org/GNOME/vte/-/commit/bd7909c961c055d772b9005a7bc112e8c898b034 It applies cleanly to current in tree 0.60.3 and seems to fix the issue.
New vte is in the tree. It doesn't have the arch keyword, but I guess it'll have to do.