Created attachment 107816 [details] screenshot of the panel See screenshot, after upgrading from 5.8.5 to 5.10.5, the icons went from nice full-height to this.
Check your desktop icon size in System Settings → Icons → Advanced → Desktop, this size will be enforced as a maximum for panel icons so they don't grow super huge anymore.
Err, the "Panel" icons, obviously.
Thank you!