I'm reviving this issue. I've noticed many times that when moving the mouse across the register that the hard drive access is going crazy. Finally decided to do a search and see if anyone else had the same issue. I found a post that spanned from 9/2020 to 11/2021 where several users reported the same issue.
https://community.quicken.com/discussion/7880898/extremely-high-disk-access-when-moving-mouse/p1 However that discussion has been closed. Has a fix for this ever been created? Thankfully my Quicken file isn't being written to my SSD, but it is still alarming the amount of disk writing that is happening.