I’m also seeing this issue still on 2013 Mac Pro AE CC 2018. The suggested Cache display ‘fix’ doesn’t seem to have any effect.
I’m often working with hundreds of Ai layers within a composition and selecting (for example) the position property by dragging a lasso (and dragging) around 200 layers as they scroll down the timeline takes FOREVER!
These are plain Old 2D illustrator layers, no Constant Raterise, no 3D, lights, motion blur etc.
2013 8 Core Mac Pro, 64GB RAM, TB 2 RAID0