I been having my iud mirena (levonorgestrel) for about a year and two months and i started spotting. i don't know if that is normal.

Yes: Light, late or no periods are expected on mirena (levonorgestrel). Up to 50% of women have no periods on mirena (levonorgestrel). That does not mean that it will always be that way. Occasional spotting is typical.

Not uncommon: Spotting with the Mirena (levonorgestrel) IUD is not uncommon. If you have additional issues with low abdominal pain, fever, chills, foul discharge, [pain during intercourse or heavy bleeding you need to be evaluated.

It can be: You can have breakthrough bleeding any time you are using Mirena (levonorgestrel) so it can be considered "normal." Since this is your first time with any breakthrough bleeding I would suggest getting checked to make sure you don't have any infection or other problem causing the bleeding.