Repairing an I nconsistent home button

My home button has become more and more inconsistent. It now requires me to push only the lower-left edge with just my finger nail. While uttering a short prayer. In a circle of candles.

I purchased a new button from iFixit and had the beastie apart when I thought I'd try reseating and reassembling the device. To my pleasant surprise, it worked. For a short while. The problem is rapidly growing worse again after less than a day of use.

I'm looking for any suggestions on troublshooting/repairing the actual button so I don't lose my fingerprint sensor. Any ideas?

Thanks!