What you are seeing is the surface of the buds being dry and freaking out over the fact that you think the whole bud is as dry as the surface. You still have moisture in the interior of the bud that is gradually migrating to the outer layer, hense the moistness of the bud after a few days in the jar. Thats what jarring/curing is all about, controlling the total moisture of the bud. I usually check my jars once a day, if the buds feel too moist I either leave the jars open for a couple of hours or if they are really moist I dump them into a cardboard box, which will help draw the moisture out.
I cant count how many times I thought the buds where much too dry. Jared them up and checked a few days later and found them to be moist again. Its a slow process fur sure. I kind of use the squeeze test. If I squeeze the dried bud gently, and it bounces back rather than stays squashed then it just about right. But you are using a hydrometer so you know what the humidity is inside the jars anyway. ( The humidity inside the bud will be greater than inside the jars because the meter is reading the air humidity around the buds) .
Just keep checking them daily and don't freak about it. I find it takes a couple of weeks to get the moisture stabalized to the level that I like it to be.
Happy tokeing