When I used to work on Saabs, they all had a cracking issue in the dash, and the rivets the held the glovebox together would telegraph through the vinyl ad make bumps on the outside. The cars that where treated regularly with Armor All, where always in far worse condition than those that where neglected. Was always fun to replace entire dash pads for the Saab cult members that where embarrassed by all the cracks, made them look like they never cared for the interior.
Whatever it is that makes the dash all shiny seems to harden and then they crack like

in cold weather. I only use Lexol products on my interior.
Either way, what are you driving? what year? what country? what color? I assume its not black?
It may be mildew.