Was it a different brand or batch of OPKs?
I would see what your temps so over the next few days. It might be a temp spike for a different reason and itll could go back down again.
What would a dif reason be?
Any number of things depending on how you take your temp like taking it later than usual or moving around before taking it.
There could also be other factors like illness or if youd had any alcohol the night before. Anything that raises your body temperature.
Stress can also raise your bbt. If I didn't feel confident that I Od then I didn't. My temp would go back to preO temps. I only did opks once a day around 4 p.m. and my surges lasted 2 days. I know some women's surges are shorter.
In short unless you feel confident you Od, I would assume it's a "faulty" temp spike.