The unit is broken/not working obviously. 80% is like room humidity. 90% during rainy days.

The sponge in the TE dislocated, hence can't fully transfer the moisture out.
You can either send it for repair if underwarranty. Or repair yourself by opening the TE unit from the back.

You are welcome. I used to help ppl service and repair drybox in my area

no, not the BIG one, the small piece, like really small, 1-2cm long, 2-3mm wide only...

usually if its spoil, it become rotten
then u cut off a small piece from the big piece to replace it.

even the sponge is dislocated, the RH wont goes up to 80, it only maintain at 50-55%RH...

as for temperature, it doesnt affect your RH (actually it will, but its very physic stuff)... u can have 10degree with 45%RH or at 50degree with 45%RH, it doesnt matter where your RH is main priority.

for RH that goes up to 80% mean the TE is not working at all.