Static on screen, but only when using ifixit battery

See photo. Any ideas?

• ifixit Apple Watch (45 mm Series 8) Battery
• Apple Watch Series 8 (GPS + Cellular) 45mm Aluminum Case with Midnight Sport Band - M/L - Midnight - Model MNVL3LL/A

The ifixit battery arrived quite low, 2.35V on my multimeter. Another arrived at 1.87V. I installed the 2.35V one according to instructions, but the device would not power on. I left it overnight to charge. It reached 4.30V. However, It will not boot when off the charger. When placed on the charger, the static screen pictured shows up. Holding the buttons for 10 seconds will turn it off, but not back on. It turns itself on, to that static screen, when placed on the charger. I followed the instructions again to put the original Apple battery in again. The device returned to working as normal. It boots and powers up fine when off the charger. So, it doesn't have the problem with the original battery, just the ifixit battery.

Any ideas? Thanks