Yes. Too much humidity is not a good thing. Especially when the tubs and enclosures we keep these animals in suck with regards to air flow.
Humidity breeds mold, fungus, bacteria, etc. If waste is not cleaned up quickly and thoroughly and can rapidly lead to unsanitary conditions.
50% humidity is fine as long as you don't have to spritz the heck out of the enclosure. At 70% you are over the limit of what most of these set ups can handle in terms of air flow.