Ghost inputs on FP4

Hi and welcome to the forum

Given that the two you have the same issue I would think it is the setup.

If you have and SD card formatted as internal that can cause issues.

You can try a Safe Mode start which disables any custom apps

Another frequent issue is using 5G try and remove that from the options.

An example of how a weak 5G can cause upsets

https://forum.fairphone.com/t/fp4-reboots-spontaneously-with-weak-5g-signal-does-anyone-else-experience-that/97760