Echo after phone reassembly

I’m having an issue with an echo heard on the recipient side of calls after fixing my Pixel 2. I followed the instructions for the battery replacement kit and ended up needing a new display. Since I needed to order a new display I ended up ordering a new charging circuit as well (the original USB-C was super loose). I completed the charging circuit replacement (and saw the note at the bottom about remembering to move the microphone board over as well). I put the phone completely back together, and before sealing the display with adhesive, powered the phone on and made a brief call to verify all was working and sounding good.All has gone well in the 1 week since the repair. I’m finding now though that recipients of my calls hear what they describe as an echo of their own voice, delayed by a few milliseconds. The echo can’t be heard from my end and I’ve verified it with a few more calls. I tested a little bit more, and when I turn speaker-phone on my end, my call recipients claim the echo goes away.