Flatpak application icon not shown in menus and panel in Fedora 40 KDE

I installed a Slack and Spotify via Flatpak but their icons don’t show in the application menu of Plasma 6. It shows fine for Spotify when application is running but not when it is closed and pinned to the task bar. I never had these issues on OpenSUSE, but since I’m new to Fedora, I might have missed something. This is a fresh install of Fedora 40. Thanks in advance!

Update: after reboot the icons show as expected. Not a critical bug, but still problematic.