What happens if I don't unmount usb before putting Link to sleep?

[roughnecks]

Hi,

just a moment ago I turned off my SteamLink (via software, I didn't unplug the cord) and I unplugged my usb key, forgetting to unmount it first.

I then connected the usb to my PC and did some changes to its files. Plugged back to my Link, turned it on with my controller and tried running Retroarch: when I went to load content, nothing showed up in the /mnt/disk folder, so I went back to SteamLink menu and run usbmounttoggle; I expected it would work as usual but I was wrong, no files found.
So I unplugged my SteamLink and plugged it in again, this time my usb key worked as usual.

So, my question is: what happens if I forget to unmount the key before turning off my Link? If I'm leaving the key plugged in and boot up my Link afterwards, will the key still be mounted or unmounted? Or, will it work at all?

Thanks