I have the exact same problem. One of our clients started having extremely slow load times and I also saw the affected machine going through every file in the attach folder. It also goes through every file again every time he performs an action which results in unusable performance. Quickbooks Tool Hub, Quickbooks Clean Reinstall, Quickbooks Repair, QuickbooksInstallDiagnosticsTool, and new User Profile did not resolve it for me.

I'm glad to see it's a known issue because it was driving us crazy.