shift modifier on touch screen-only tablet no mimicking std keyboard

[dlarue]

Describe the bug
Shift key modifier does not activate nor release while a character key is held continuously.

To Reproduce
Steps to reproduce the behavior:
open a terminal window, bring up the OSK and hold down the 'd' and see it repeating ddddddddd
Now try to press the Shift key while continueing to hold the 'd' key and it will not produce dddddddDDDDDDD

Expected behavior
The Shift key should implement modification of the key being pressed even during repeat mode when a key is held down.

Environment (please complete the following information):
PopOS 21.10 v3
Gnome version: 40.5

Additional context
I'm trying to use a feature of a laser cutter software which turns on the laser at low power during the framing operation. They have a Frame button which when pressed with the Shift key modifier pressed, it triggers the lower power laser firing operation.