Hi nonnieto2,
Thank you for the response. This might be a hardware issue. Please check if any keys are stuck on the keyboard. Please check individual keys. I would suggest you to try to Create a new user account and check if the issue persists.
If the above steps do not produce any positive result, I would suggest you to re-seat the keyboard. You may refer to the Service Manual. Please ensure to follow safety instructions mentioned in the manual.
Please share the findings.