The System on the Zenfone 8 flip became unstable since the last update.
For the first time (since turning on in July 2021.y.) it often restart itself.
All the best
Try to reset your phone
Maybe there's some conflicts when you updated it
Thank you very much for the advice ; but too much work and too much time. I reset the phone only when I give it to someone else to use.
All the best!