It could be a humidor problem, it could be your sponge is no longer holding moisture. Your temperature is a little high, 75 and higher and you have to start worrying about Tobacco Worms/Beetles. But humidity between 63-70 is actually not a bad thing, that's a good range. It's all personal what level you like in between those. There are some people who like 75% humidity. Check out this link for all humidor questions. Briefly though, if your humidor is solid (i.e. no glass), then do the flashlight test. In a perfectly dark room, place a flashlight that is on in your humidor, if you can see light, your humidor has a leak.

http://www.cigargroup.com/faq/#5.0