Has there been a problem with the mechanical keyboard?
Has there been a problem with the mechanical keyboard?
OK, this appears to be a membrane keyboard, not a mechanical keyboard. If so, any of the advice about switches is not applicable.
Your best bet is to take the keyboard apart and make sure the membrane layer is still over the keys and there's no detritus or anything sticky inside. If that doesn't work, the PCB might be damaged.
I discovered the membrane was damaged, which meant I needed to purchase a new keyboard.