Can child birth change ovulation?

Probably a silly question, but I'm just at a loss here. I'm 5 months post partum, and my cycle resumed right on track, and has been cycling pretty much normally since delivery. I got my period this month on the 14th of this month, and it ended on the 19th. My period tracker app shows that my peak day for ovulation is tomorrow, 10-29. Since yesterday, I've noticed dull period like cramps and brown spotting. I know this can be a sign of ovulation, but I have NEVER experienced it prior to yesterday. Is it possible pregnancy and childbirth has just changed things out of the blue like that? Or should I see a doctor?