I am a little late responding here but hopefully this will help. There are several things that could cause that.
First off, it looks like either you have too much geo or you have not rubbed/tapped or wrapped the cheese during aging to flatten and compact the rind. You can try using less geo (or no geo at all), or switch to a different strain of PC with a more shallow growth. The formation of thick rind early on not only locks in moisture but it also accelerates ripening activity too much, which is like cooking something cold on high heat instead of medium heat - the exterior overcooks before the interior had a chance to.
Two Other contributing variables to factor in are 1). The aging temperature (how warm was it? Try not to go over 55F) and the pre-draining period (did you pre-drained in a cheesecloth or strainer first? If you didn't - you'll end up with overly-moist curd. You can be generous and give it 12 hours to pre-drain before scooping into the molds).
Lastly, with such thick rind in only 10 days I can only assume that your pH was rather high and neutral (maybe 5-5.5?), which means the cheese might have not been acidic enough. How long did you coagulate it for? If you measure pH, it should be around 4.5-4.6pH when you pre-drain it. Post your recipe or make log and we will figure this out.
