That's a Great Question:
In the 6 years I used Gen #1 MES units, I never had that happen.
Now during one of my smokes I noticed a puddle of water around the right front foot of my new Gen #2.5.
I just laid a couple paper towels there to suck it up.
I figured it was just the condensation that kept forming on the inside of the window & running down, but I don't understand where the condensation went all the times I used My Gen #1 ????
I only noticed it one time, so it might depend on what you're smoking & how much humidity the current air can handle.
Bear