Worms clumping together in bottom bin. Should I be worried?

I have two stacked bins, with food and bedding in the top, and worm poop in the bottom. I’ve noticed a lot of worms (like 100 of my original 500) have settled in the bottom bin and many are clumping in groups of 10-20 on the walls or the top of the bin. Has anyone else had this?

My moisturize levels seem ok and the pH levels were getting a bit too acidic, but I added crushed eggshells a few days ago to help.