If I chose the default "GNOME" option in GDM the system uses Wayland. In
this instance resizing a gnome-terminal window does not bring up the
tooltip that shows the new size, which makes it difficult to resize to a
particular rows/columns combination. Switching back to GNOME on X11
fixes things.

I suspect this is something down the line from GNOME Terminal, but I'm
not familiar enough with the stack to assign more intelligently.

Control: tags -1 + upstream

This is a known issue upstream. In X11, the window manager (not the
terminal) is responsible for showing that tooltip. In Wayland, the app
(the terminal) should be responsible for it, but there's currently no
API for GTK+ (or possibly GDK) to communicate to gnome-terminal that the
window is still being resized, so the least bad implementation possible
would be a heuristic.

    smcv