Button cell doesn't maintain RTC on Seeed Studio expansion board w/XIAO samd21

The button cell doesn’t keep the RTC running? This is a great product with all of the inherent features working 100% except the RTC isn’t maintained upon a power loss?
I have reloaded the RTC example several times to no avail. I don’t believe I’m doing anything wrong. The board acts like a internal sw (ic) is open? I have this product running constantly and am very pleased with it. I guess I will have to buy another if something is internally wrong?