Hi,
I'm seeing this issue appear namely with Synology Cloud Station Drive, which is a third party tool that's installed via the instructions on this page: https://getsol.us/articles/software/third-party/en/
I understand that as a third party tool there's only so much the Solus dev team would support, but I'm not sure if this would relate to other apps.
Anyway, if you see the screenshot you'll see the issue - the icon on the left is the proper one for controlling power and user login/logoff - but the icon next to it is for the Cloud Drive app. I haven't observed this with other apps yet I don't think, but I remember a couple months back or so there were some updates to the system tray icon handling, and this started occurring.