MSM Notifier only allows opening "Kernels" and/or "Language packs" menu items once per system boot and the "Options" menu item also stops opening after either of the first have been opened on a boot
It's been like this for months by the way, but I'm not sure when it started happening.
It happens even if you don't use anything in the windows opened from the menu, just opening the window triggers it.
I'm running Manjaro XFCE on two systems which both have the issue.