When you open the camera up, for any reason, you are introducing humidity into the sensor chamber. The ASI cameras, the cooled ones, use two sealing rings (silicon rings) in the front sensor chamber, one around the screw section if the front cap, and the other is under the AR glass sensor window opening. If you open the camera to change dessicant pills make sure you do so in a dry room if possible. When i change mine i use an Argon box but that is not really necessary.
Also, ZWO now make a heater for their cameras:
https://astronomy-imaging-camera.com...ti-dew-heater/
I highly recommend this $19 USD heater as it stops any fogging, frosting, etc. I have been running one for months now.