Keyboard re-captured with no clear reason

[ctrl]

I'm on a laptop with classic brightness and volume control hotkeys, and when the keyboard and mouse integration is active in the guest these hotkeys don't work but that's expected, I'd say (keyboard backlight control always works, though).

So I press the host key, right ctrl, to disable integration, and that kinda works, but only for a brief moment. Meaning:

• I press host key, icon goes from green to black.
• I can wait forever and nothing happens (ok)
• I press volume up or down, volume is changed in the host
• After about 1/2 sec the icon goes back to green and integration is active, hotkeys don't work anymore in the host.

Even more strange is the behaviour with brightness control:

• I press host key, icon goes from green to black.
• I press dimming up or down ONCE, host screen is affected
• I can wait whatever time I want
• I press dimming up or down again, host screen is affected again
• After about 1/2 sec the icon goes back to green and integration is active, hotkeys don't work anymore.

Maybe it has something to do with windows focus because these hotkeys trigger on screen notifications, but the integration is reactivated well before the notification is gone, and for brightness it only happens on the second event, so the first notification does nothing.

I know it's more of an annoyance than an issue, but still...