Keyboard sticking

Music studio lite and paid version
Oukitel K6 Android v7.1

Single keys work fine but press à chord of 3 keys simultaneously and they stick. When pressing the stuck keys, usually 2 will unstick but one will remain stuck and unresponsive. If the keyboard is scrolled the key can then be unstuck.
The screen works fine in other programmes such as Caustic.

It’s annoying to keep typing a word because of the stick!
Only a new keyboard replacement!
Anh Duc Water