MacBook Pro Early 2015 double typing after Big Sur update

Reset  SMC:   How to reset the SMC of your Mac - Apple Support   Choose the appropriate method.

Quote:

Resetting the system management controller (SMC) can resolve certain issues related to power, battery, fans, and other features.

Startup in Safe mode. https://support.apple.com/en-gb/HT201262 Choose the appropriate method.

To leave Safe Mode, choose “Restart” at the bottom.

Quote:

Safe mode prevents your Mac from loading certain software when it starts up, including login items, system extensions not required by macOS, 

and fonts not installed by macOS. It also does a basic check of your startup disk, similar to using First Aid in Disk Utility.

 And it deletes some system caches, including font caches and the kernel cache,

 which will be created again automatically as needed.

Antoine Humblet wrote:

Hello,

I have just updated my MacBook Pro Early 2015 model to the latest firmware available (Big Sur, 11.4). Since the update, I am experiencing random double keystrokes when I type. For example, if I type the word "example", it would type instead "examplemple". Same happens with spaces, the arrow keys, and so on. I have already checked the keyboard settings in the System Preferences and fiddled with those, but no results yet. Anybody has this issue and can help ? This is getting quite frustrating.

Regards,

Antoine

Try resetting NVRAM/PRAM http://support.apple.com/kb/ht1379