TouchID sensor showing signs of condensation/moisture accumulation

Hello

I've been experiencing this issue for years now. It started with my iPhone 5S and I hoped it was fixed with the 6S but after a couple of months it started showing again with my new phone. Basically what I'm experiencing is very basic condensation accumulating on the touch ID sensor. This prevents it from registering my fingerprint and I need to wipe it several times before I can get the sensor to start working again. Another strange phenomenon is that after I wipe it and I set it aside, the thin moisture layer accumulates again in 2-3 minutes and I need to wipe it once more. This defeats the entire purpose of the touch ID sensor since I end up inputting my password every single time I need to unlock my device. It's also good to note I live in a relatively dry environment and this occurs both indoors and outside. The temperature difference outside and inside doesn't make any difference whatsoever. I also tried using a case to see if that might fix the issue...and it didn't, issue still persists. Can someone share their thoughts on the matter since this is proving to be really annoying and I might end up returning my phone.

Thanks