Replaced battery, now computer shuts down randomly

My battery wasn’t doing great so I replaced it with a battery from iFixit. Replacement went fine, battery was charging, but now, I can be working on battery power and suddenly the computer will turn off. Not shutdown, but a complete power pull. It’s as if the battery is suddenly not recognized. The first time this happened, I fixed it by opening up the case again and making sure the battery was properly seated, which it was. It has since happened again, and upon powered reboot, the computer doesn’t recognize that there is a battery there.

I’m at a loss as to why this is happening and would appreciate any assistance.