I have bought a Meizu M6 in April 2018. Unfortunately, I dropped my phone and it cracked. We ordered a screen + digitizer and replaced the screen. By replacing the screen, we accidentally damaged to power button ribbon. So we ordered a new on and replaced it as well.

It started to work again - however, after about two days, it had instant shut downs and when we tried to charge it, the phone displayed that it had a battery percentage of about 54%. When we tried to turn it on, up to the flyme sign it was looking good, but then it shuts down again. After waiting for about 10-15min, it turns on again and the battery percentage was at 46%.

We opened the phone again to check whether the ribbons and everything else was in the right place.

We also followed the instructions online to calibrate the battery. We used it until it shut down by itself and it did not turn on again. After plugging it in, the battery life was at 74%, after turning it on it was at 53%. We observed that the sudden shut downs happen below the battery percentage of 50%.

Is it possible that the phone needed to be grounded while trying to fix it?

Should I replace the battery? - it really should be fine after only 2 years?

Before I go to a shop, spent the money, and run diagnostics, I wanted to check here whether someone experienced the same? or has any recommendations?

Cheers,
MP