Since I have been testing the UPS and associated software on a new installation of Raspberry Pi OS on the same Pi4 but without MotionEye, I have not seen i2c errors in the journal. The camera is still connected and enabled.
On the old installation with MotionEye installed I had regular i2c timeouts but eventually they were all handled by your script, yet clearly logged in the journal. I could even see in what part of the code the exception occurred. Very reassuring. My own attempt at exception handling didnt' provide that information, so your code will be an example for when I need that again.
Anyway, it so seems that having MotionEye installed is linked with the i2c errors.
In the end I will go back to that installation (other SSD), because one of the goals of that Pi4 is to run MotionEye. We will see then what happens.
Since I have been testing the UPS and associated software on a new installation of Raspberry Pi OS on the same Pi4 but without MotionEye, I have not seen i2c errors in the journal. The camera is still connected and enabled. On the old installation with MotionEye installed I had regular i2c timeouts but eventually they were all handled by your script, yet clearly logged in the journal. I could even see in what part of the code the exception occurred. Very reassuring. My own attempt at exception handling didnt' provide that information, so your code will be an example for when I need that again.
Anyway, it so seems that having MotionEye installed is linked with the i2c errors.
In the end I will go back to that installation (other SSD), because one of the goals of that Pi4 is to run MotionEye. We will see then what happens.