Apple Pay and Bluetooth connection not working

I recently replaced the screen on a Apple watch 3 GPS with a donor screen from a series 3 LTE, i replaced the gasket and sealed the watch up, the display works great but now i am having problems with Bluetooth connection. the watch will connect to my phone and pair, but will loose connection when my phone is in my back pocket and the watch on my arm, i cannot walk away from the phone without loosing signal. also apple pay doesn't work which seems to be a common problem.

my question is this watch is still under apple warranty. should i risk sending the watch in to apple? i already opened a case and they have sent me a box to send the watch in. but i assume they will notice that i have replaced the screen and possibly not cover the Bluetooth issue.

any advice or assistance would be appreciated. i feel like i am stuck with a useless watch now.