OEM LCD Screen freeze after snap into back housing.

Need help with all the expert from all over the world.

i been fixing iPhone 6 since the next week it came out.

Now i have a new issue. I myself refurbished OEM LCD and i only use OEM. not after market.

So what happened is this iPhone 6 freeze whenever you snap completed assembly LCD into the phone and it always working Ok before you snap in it.

No ghost touching. just freeze.

So i thought it might be because of the back metal plate and the LCD flax cable plate cover.

I took off the plate cover and i changed LCD back metal plate as well. but it's the same. the original metal plate has broken and it doesn't work with figure touch ID.

i even change the whole back housing and transfer every single pieces from the original phone. because i though the metal plate touch board and short due to the bent.

i was thinking, it has short somewhere left side near volume button and below.

I wanted to get advice from you all.

Like i said, it's always working OK before you snap into the phone. and i am 100% sure that my LCD doesn't have a problem. because i tested with 3 different LCD. all OEM. all 100% work with the others board.