I'll be trying this tonight and I'll let you know if it makes a difference, but I was thinking of mixing a dryer substrate, taking out scoops of reptichip and trading it with reptibark or a dryer batch of reptichip.
Here's a follow up; Swapping out/mixing Reptichip with Reptibark was a success! Humidity is now at 70-76% and has been holding since last night instead of rising during the day.

Sounds like you've done something similar, how is it doing for you?