Certain keys on keyboard work inconsistently

I have rebuilt a Surface Laptop 3. I applied the most current firmware update. I applied all Windows updates. As I am typing, keystrokes are randomly missed. For instance, I will press the 'F' key and it may not recognize the key had been pressed. Additional keystokes to the same letter will then work. This is happening on a couple of keys. This is happening on more than one of our Surface Laptops and I don't think it is limited to the Surface Laptop 3. I don't feel it is a hardware issue. Almost feels like an interrupt issue that disrupts the recognition of the key being pressed. Help...