Mini HDMI to SDI 12g doesn't ouput 1080p

I connect HDMI from PC to mini HDMI to SDI 12G and select 1080p60 from Windows display setting but I still get 1080i output from the converter. Does MINI HDMI to SDI 12G truly support 1080p60?

First off There is no Mini Converter HDMI to SDI 12G. The mini converter series goes up to 6G.
So i expect we are talking about the Teranex Mini ??

Have set the downconverter on?
What device are you using that you know it outputs 1080i ??