Breakthrough bleeding halfway through Yaz pill pack...?

Hi everyone. I've been on Yaz for 7 months now and experienced breakthrough bleeding for the first 3 months or so. After that, my cycles were essentially normal with no spotting or bleeding between cycles. However, this month (7th), 2 weeks into my new pill pack I have started experiencing dark brown breakthrough bleeding. The bleeding is a little bit heavier than spotting, almost like a normal period. I will either wear a pantyliner or small tampon but the bleeding is not very red in colour. Is this something I should be worried about, or is it just your run-of-the-mill breakthrough bleeding? Also, can something like taking your pill 1 or 2 hours later than normal for a few days also cause this?