Hm. Well, I wouldn't say that is normal but also not totally uncommon. Some women get some break through bleeding around the ovulation time and it happens as the egg bursts through the follicle. This also could be hormonal in nature. Or another real possibility is cysts on the ovary. Women have these and they are often harmless if they have a single one or an occasional one. If they are chronic, PCOS is then an issue which is polycystic ovarian syndrome. I have had a simple cyst before that passed on its own. Most women will get one at one time or another. I hate to bring this up but also HPV or issues with the cervix can cause mid cycle spotting. So, overall, you need an evaluation by your doctor to fully understand what is going on here but most likely, this is not going to be very worrying for them (or you).