Thanks for the query.
It is a common side effect while on oral contraceptives, to have some kind of irregular spotting.
Also, it is more common during the first month of pill use, and particularly, as you mentioned, when you stop the pills and resume again after a gap.
So do not worry about it.
Please take the pills on time, do not miss pills and see to it that you are not taking any other medications which affect the efficacy of oral contraceptive pills
Moreover, you should have regular follow up with your health care provider to rule out any other problems which cause spotting.