I have a heat pump (aquacomfort) and it too will ice up from time to time but when this happens it automatically kicks into "defrost" mode and takes care of it. I have only noticed ice buildup when running in the pump in cooler temps, I know your post says it is 75 but was it running overnight or something when the air was cooler? In any case, I would check to see if it has a defrost mode and if so I would consider letting it run and see if that kicks in automatically.
Mine also has a water flow sensor so would switch off automatically if that was a problem so would guess you might have that built in too.
So, in short, the pump may well be operating as designed but read up in the manual and check it out.