I think the answer here is clear: Although your daytime humidity is kinda on the higher side (but fine), your night time humidity is not high enough.
I shoot for around 85-95% (80-100% is recommended).
What does your actual misting/fogging schedule look like? Keep in mind that short bursts of higher humidity aren't likely to be enough. Considering they're not typically drinking and just 'absorbing' the humidity, they likely need the higher humidity for a longer period of time.
Are you able to get an automatic mister and a fogger?
For example I am misting at 7:30pm, 1:00am, and 6:25 am
Right now I am misting for 60 seconds each time. However, I am also fogging from 1am - 6am.
This helps keep the humidity in the mid-high 80s+ all night/morning long, starting at 1am.
If you are just misting by hand, I don't think it's enough (For your situation specifically. for others...this can work).
As suggested earlier by
@elizaann2 , to give your chameleon a hydration boost, I agree with offering some hornworms/silkworms to help your chameleon immediately. I personally feed silkworm(s) to Spike daily. But I feel like you need to make adjustments on your misting/fogging in general. I think that's the real issue here, if I am not mistaken.
With a humidity of 60% I would never mist/fog during the day. My humidity during the day is typically 45-60%+ and I would never even consider it. My male panther has done excellent with only hydrating at night while he's asleep. But I am also making sure that his humidity is consistently high (above 80%) from 1am until 6:00am. So he is being hydrated that entire time (not just in short spurts). I hope this helps!
edit: If you are already on a schedule, maybe you simply need to increase the duration of your mister. In the winter I found out that I had to actually increase my misting from 60 seconds to 120 seconds to reach the humidity I wanted to achieve at night. And now I am back to 60 seconds.