Left clicking an open program in task manager is opening another instance of it

I'm getting a bug where left clicking a program open in the task manager triggers opening another instance of the same program instead of raising/focusing in the already opened window. This didn't happen using X11. It's not the behavior configured for the left click; a recently started session works fine. The only way for it to go away without restarting is entering Plasma's edit mode and exiting it - then task manager behaves ok for a while. How can I trace what causes this ? I tried checking journalctl for criticial errors or logs when I click and this behavior happens but couldn't find anything relevant

Plasma5, wayland, nvidia