Oh, very interesting regarding it being slightly swollen. Do you charge it for extended periods of time? Glad that they found the fault and were able to rectify it.
Replace the battery and see if that resolves the shutting down issue as it only shuts down when it's on battery. Sounds like a faulty battery controller misreporting to the system.
I've had this phone 2 years and I've never experienced random shut downs. You have to realise that complaints you read about online are from the minority. Most people with good experiences don't comment online.
I am happy with the phone apart from the proximity sensor issue when on a call which is a big issue tbh. I couldn't care less about security updates being a few months behind and the quality of life features.
What bugs are you experiencing? The only bug that I have is the proximity sensor not working as it should when you're on the phone you need to lock the screen or your face touches areas of the screen. I've had to download a 3rd party app to mitigate ...