I'm going to take a wild assed guess that's yet to be put forth. We can tell from the data you provided us that they are not holding humidity as well as they should. I see that you live in south Fla. Has the weather gotten (relatively) cooler lately. I ask because at the height of heat, your AC is cooling and trying to keep up. As temperature drops a bit, your AC becomes essentially a giant dehumidifier.
If the above is the case, I would argue that this is no surprise. I would also add that if they are truly 50-60% for any length of time, this will not harm the sticks. Just relax and stop fighting nature.
If the above is not true, I just made my arthritic finger hurt for nothing.
