If you find irregular surfaces at the glue line in wood projects, the problem can be moisture levels. This can happen, for example, when one piece has a 15% moisture content, while those next to it are at 8%. If you glue and plane boards with unequal moisture, those with higher moisture will eventually shrink more than those with less moisture.
Never store paint where it will be subjected to subfreezing cold or extreme heat (over 100 F/ 37.78 C). Although most paints are formulated to withstand several freeze-thaw cycles, these conditions can ruin coatings by causing then to solidify.