This bug has disappeared by an upgrade about a week ago.Apparently, the problem was not caused by gnome-terminal: downgrading from version 3.26.2-2 to 3.22.2-1 does not re-introduce it.
In any case, feel free to close this bug.
- Bug#850024: gnome-terminal moves, while it's being resi... Richard B. Kreckel
- Bug#865209: gnome-terminal: Resizing terminal wind... Richard B. Kreckel
