Are you by any chance getting error messages like this in dmesg?
[4335062.871000] atkbd.c: Use 'setkeycodes e02a <keycode>' to make it known.
[4335063.546000] atkbd.c: Unknown key pressed (translated set 2, code 0xaa on isa0060/serio0).
[4335063.546000] atkbd.c: Use 'setkeycodes e02a <keycode>' to make it known.
[4335063.607000] atkbd.c: Unknown key released (translated set 2, code 0xaa on isa0060/serio0).
[4335063.607000] atkbd.c: Use 'setkeycodes e02a <keycode>' to make it known.
[4335073.996000] atkbd.c: Unknown key pressed (translated set 2, code 0xaa on isa0060/serio0).
[4335073.996000] atkbd.c: Use 'setkeycodes e02a <keycode>' to make it known.
[4335074.114000] atkbd.c: Unknown key released (translated set 2, code 0xaa on isa0060/serio0).
[4335074.114000] atkbd.c: Use 'setkeycodes e02a <keycode>' to make it known.
If you are, they might be caused by a service called "hotkeys-setup". I've been having a problem with a stuck ctrl key across several releases and configurations of Ubuntu, and removing hotkeys-setup now finally seems to have solved the problem.
Are you by any chance getting error messages like this in dmesg?
[4335062.871000] atkbd.c: Use 'setkeycodes e02a <keycode>' to make it known.
[4335063.546000] atkbd.c: Unknown key pressed (translated set 2, code 0xaa on isa0060/serio0).
[4335063.546000] atkbd.c: Use 'setkeycodes e02a <keycode>' to make it known.
[4335063.607000] atkbd.c: Unknown key released (translated set 2, code 0xaa on isa0060/serio0).
[4335063.607000] atkbd.c: Use 'setkeycodes e02a <keycode>' to make it known.
[4335073.996000] atkbd.c: Unknown key pressed (translated set 2, code 0xaa on isa0060/serio0).
[4335073.996000] atkbd.c: Use 'setkeycodes e02a <keycode>' to make it known.
[4335074.114000] atkbd.c: Unknown key released (translated set 2, code 0xaa on isa0060/serio0).
[4335074.114000] atkbd.c: Use 'setkeycodes e02a <keycode>' to make it known.
If you are, they might be caused by a service called "hotkeys-setup". I've been having a problem with a stuck ctrl key across several releases and configurations of Ubuntu, and removing hotkeys-setup now finally seems to have solved the problem.