Problem with capacitive keys

Just started testing the unofficial Pie upgrade for Santoni (Redmi 4x): e-0.7-p-20191025-UNOFFICIAL-santoni.zip

The phone has captive keys below the screen.

When I switch-on the on-screen navigation buttons in settings, the captive keys still remain functional (additional to the on-screen buttons).

Desired functionality: When the on-screen navigation buttons are enabled, the the captive keys should remain disabled.