This case had an issue that caused the buds to stay connected, even after being inserted into the case. However, if the case was plugged in, everything worked as expected. So, this lead me to try swapping the mainboard with another unit.

Once the case is open, carefully slide the halves apart. There is a thin ribbon cable connecting the parts.

At the bottom is a thin plastic separator on top of the main board applied with a small amount of adhesive. You should be able to easily pull it up out of the way.

Underneath, you'll find the main board held in place by two screws. One is highlighted in the picture, the second is above it to the right.

Remove the two screws, then to remove the board use a toothpick to push on the USB connector from the bottom. This will make it easier to dislodge the board, allowing you to remove it from the bottom