I had that same problem on my first couple of hatches. Different areas need different humidity levels, depending on the time of year and the humidity level in the area you live in. When I tried lowering my humidity to 25-35% during incubation and 60-65% during hatching, the problem stopped.
Another idea for disinfecting that has worked well for me is alcohol. I just clean thoroughly with bleach and soapy water, gently scrubbing it with a brush. Then I put alcohol in a spray bottle and spray it down, even around the motor. It helps it dry faster, won't damage the electrical, and kills 99% of germs.
Good luck with the rest of your hatch.
Another idea for disinfecting that has worked well for me is alcohol. I just clean thoroughly with bleach and soapy water, gently scrubbing it with a brush. Then I put alcohol in a spray bottle and spray it down, even around the motor. It helps it dry faster, won't damage the electrical, and kills 99% of germs.
Good luck with the rest of your hatch.