Huawei p20 lite constantly locks

I have recently replaced my phone as my old p20 lite constantly locks itself, I tried all the usual things, updates and factory reset.

There was a few suggestions about actual settings on the phone being the problem so I have tried changing them as well.

Some times it will be OK, other times it will lock before you have finished typing in the 6 digit pin.

I haven't actually taken the device apart yet, but is there anything I could replace or should be looking out for other than the obvious?

It was a great little phone and I just want to foz it out of curiosity to be honest and wouldn't mind having it as a backup phone either.