BBT significantly lower than usual…

R

My BBT has been a lot lower this cycle and I’m not sure why. Like more than any of my other cycles, regardless of being pregnant/not pregnant or when I ovulated or anything.

All of my other cycles as long as I’ve been temping (a little over a year maybe?) my temp post ovulation are around 97.5-98.0

But this cycle my temps have been low before and after. The highest my temp got was 1 day after what I THINK was ovulation (and it spiked to 97.4 or 97.5)

But ever since then they’ve only been around 96.7-97.1

Anyone know why this would happen or have anything similar happen?