Bleeding on Microgestin

Alex
Hi friends! I have been on Microgestin for about four months. It is a combination pill, so I am supposed to take it everyday for three weeks and then have my period on the fourth week. For the past three months, I have started bleeding around the start of the third week, while I am still taking the pill. Is this normal? It's not super heavy, but it's pretty much like a two week period. Please help!