I haven't found that the sensor cleaning does anything to dust spots on my sensor. Have done the test shot before, then the sensor cleaning then test again. Spots are the same.
Then rocket blower, test shots, spots same.
So when I get spots I seem to need a wet clean (all on my 5DM2)
It seems as if you may have somehow gotten something on your sensor other than dry dust. That could be why you needed a wet cleaning.
Not sure how on earth anything other than dust could have gotten on your sensor, except that maybe some type of lubricant was at one time used on your body or lens? Or maybe lens cleaning solution was in use when there was no lens on the body and the mirror was up? Not sure how that could happen, but I can't think of any other way anything other than dry dust could have gotten all the way past the mirror / shutter assembly and onto the sensor.