Modifier keys no longer honored with Dvorak layout

Question

I use linux (Solus distro) with Dvorak keyboard layout and have keyboard shortcuts e.g. Alt+Shift+T to open/focus on Terminal application.

Since last week when I press Alt+Shift+T it translates to Alt+Shift+K since T on Dvorak layout corresponds to 'k' on Qwerty layout. So the keymap is lost when modifier keys are pressed. If I don't use modifier keys then Dvorak works fine, but then the whole productivity is lost since I cannot use my shortcuts.

To debug this I started using 2 external keyboards https://i.imgur.com/zVoNH29.png both blank and dvorak, and both are working fine. But somehow the system keyboard has suddenly started sending the wrong keycode when modifier keys are used.

Please help!! I have already spent 2 days trying to understand and debug the problem using xmodmap etc, but to no avail.

here is some info on the distro in use

LSB Version:    1.4
Distributor ID: Solus
Description:    Solus
Release:    4.0
Codename:   fortitude

Further investigation into the issue reveals the problem only shows if ALT_L+Shift_L is used instead if I use Shift_R+Alt_R everything works fine. In other words using system keyboard

Alt_R+Shift_R+K is equal to Alt+Shift+K

but

Alt_L+Shift_L+K is equal to Alt+Shift+V