When not updating for a while, the taskbar tooltip shows several lines: "123 new updates available 98 new updates available 50 new updates available"
Are you refering to the tooltip when hovering the updater icon in the system tray next to the clock or the popup notification that shows up?
I'm referring to the popup notification.
I cannot reproduce this anymore. Operating System: openSUSE Tumbleweed 20220217 KDE Plasma Version: 5.24.1 KDE Frameworks Version: 5.90.0 Qt Version: 5.15.2 Kernel Version: 5.16.8-1-default (64-bit) Graphics Platform: Wayland