Control sequence '\e]104;x\a' hangs in libvte

The command:
$ printf '\e]104;x\a'
will cause either gnome-terminal or xfce4-terminal to enter an infinite loop inside libvte-2.91.so.0.

I believe the problem is in src/vteseq.cc in the Terminal::reset_color function:

        while (token != endtoken) {
                int value;
                if (!token.number(value))
                        continue;

                int index;
                if (get_osc_color_index(osc, value, index) &&
                    index != -1) {
                        reset_color(index, VTE_COLOR_SOURCE_ESCAPE);
                }

                ++token;
        }

When token doesn't point to a valid number, then "continue" bypasses the ++token line and will just re-parse the same token over again.