I'm on the mini pill Cerazette and all mini pills are known for irregular bleeding - be it spotting bloody discharge or a full on period like bleed. For the first month on it, I had a normal like period bleed and then nothing for 6 months and then it was spotting and then nothing for a few months then a period bleed then I bled heavily for a month straight almost then nothing again for a while and so on and so on. I just got used to never knowing when I will bleed. Brown discharge sounds like spotting and nothing to worry about while on the mini pill.