i am guessing due to lack of a photo of your circuit, that you do not have a low enough inductance path between your 220uf and your 2.2 uf supply capacitors, the mosfet, diode D1, and your gate drivers, which is made up of the supply capacitors, and diode D6 and the ground line between pin 6 of the ir2117 and the source of the mosfet.
this is why the weirdness shows up at around the same voltage that you're supplying the gate driver with (12 volts)
i recommend reducing the frequency to 30Khz, getting everything to work and then increasing the frequency when you have everything figured out.
in the attached photo, is where i think your mosfet is actually turning on. it is hardly even getting perhaps one volt beyond the gate turn on transition, by the time the pwm pulse is almost over, so it turns off quickly afterward.
the majority of the signal you see is noise, again due to a high inductance path, possibly the majority of which is in your oscope probe.