Can you ovulate but not get a positive opk?

Shell • One beautiful 👼🏻 in heaven Charlotte Rose 6th of April 2018. Rainbow baby boy Spencer came on his sisters anniversary 6th of April 2019🌈 👶. High school sweet hearts 💕 12 years together, 2 years married ❤️❤️ Fur Mummy to Napoleon 🐶 8 years old

Hey ladies I have pcos. I have regular periods and have for a long time. I’m not on any contraception haven’t been for a year. I wanted to know if it is possible to ovulate but not get a positive opk I ask because I get ewcm every month with out fail I’ve also had my bloods checked to make sure I am ovulating and they were perfect.

I do opk tests but they never seem to be the same colour/ darkness so I’m confused as to why this may be ?

The are dark but not as dark as each other.

Any thoughts or advice would be greatly appreciated baby dust to all ❤️