Mac shift key types 5 or mutes mac

Greetings Macshiftkey,

Welcome to Apple Support Communities. We would suggest resetting the system management controller (SMC), as this helps resolve certain feature issues. Per the Apple Support article:

1. Shut down your Mac, then unplug the power cord.
2. Wait 15 seconds, then plug the power cord back in.
3. Wait 5 seconds, then press the power button to turn on your Mac.

Complete details on this process can be found here:

How to reset the SMC of your Mac - Apple Support

Feel free to reach back out if you have any questions.

Best regards!

Thank you for the reply Macshiftkey!

Is there any accidental or liquid damage to this keyboard? Was anything updated or changed when this started occurring?

Also, would you have another keyboard you can try? If you personally do not have another keyboard, see if you can borrow a friend or family member's keyboard to help us isolate the issue.

If the issue does not occur with another keyboard, contact Apple directly for further assistance:

Get Support

Cheers!