Minnniemouse - you are still peri meno and so may be getting fluctuations in your oestrogen levels. The Mirena doesn't actually stop bleeding for everyone.
Here is the section on this site that explains about the effects of the Mirena:
Progestogenic absorption throughout the body is minimal so reducing progestogenic side effects. The effect of Mirena on the womb lining can significantly reduce bleeding and when used as part of an HRT regimen, in time, 30 to 60% of women have no bleeding at all.
In other words, some bleeding is quite normal. If you were very post meno then there could be cause for concern.
Keep using the patches, the bleeding will probably settle in time. DG xxx