One day it works without any problem, then from nowhere, phone lying on the table and the power/shutdown menu starts randomly appearing and popping up, like I would want to turn the phone off or restart it. And Im not even touching it.
I tried many different ROMs, official, custom, I took it to the samsung service and they changed the power button.
I tried different batteries, chargers, switched the main board to different s3 phone, but it still, once in a while, does that popping up power off menu thing.
If I let the menu appear for a certain period of time and do nothing, the popping up frequency gets higher and higher until it restarts the phone and then ends in bootloop.
Sometimes if I remove the battery for a certain period of time, the phone starts up and works like nothing happened a minute ago. Other times it does not boot up and stays in bootloop.
I figured out that if I continue to push power button in a one second intervals after powering the phone, it continues to boot up and starts up. I enter the PIN code and then the phone either acts again like nothing happened, or starts the popping thing again.
If I keep pushing the power button while the popping up shutdown menu is happening, I kind of cancel the whole thing and phone works okay, ending again either in no problem state and working like a new phone, or restarting itself and bootlooping.
It doen not happend at certain time or while doing any specific activity or while in specific app, or anything, totaly random thing, sometimes during the call, week later during the night, 2 days after in my pocket, 10 hours later while lying on the table.
Thank you for any ideas what could be causing this.