Humidity Gradient??

I made the switch this week to shredded coconut husk substrate and within a day my humidity meters started giving me 99% and condensation was appearing on the front of the bins. Of course me being a new snake keeper, I immediately began to flip out about possible scale rot and RIs, but today during the feeding session, I noticed I left one humidity meter in the back of the bin (I usually stand them up front so I can read through the bin). Loanbehol, it read 65%! I was very surprised.

Back when I used newspaper, I did sometimes leave the meters in different places, but their readings never changed. Somehow the coconut fiber is able to create a humidity gradient.
Maybe the UTH is drying it out in the back and the excess moisture is coming down in the front of the bin? Either way, what effect do y'all think a humidity gradient could have for BPs?

A UTH will definitely dry out the substrate under it and cause a gradient. With coconut fiber a little water goes a long way but a few days of high humidity once shouldn't harm your snake. I have a 4 foot long enclosure for my skink that can be almost 40% different from one end to the other. I have to add more water to the warm end when I'm adjusting the humidity

There is a possibility your gauge is kaput too. You could move it up to the front and see if it goes up to the 90's like the others. Acurite Digital hygrometers work good but I have had them occasionally malfunction. Like the one my snake just dumped into it's water bowl. Had to replace it. It is good to check them side by side to see if they are all working and showing the same numbers. One time I kept misting and misting come to find out it was a bad reading. When I replaced it the humidity was great.

Not saying what you said can't be true. Like one said the uth could make it dryer at the back. You should read the other thread about spiking humidity to get some additional tips and info.