i think that's normal windows behaviour.
In case 1, windows removes it from list of drives to show, but does not bother to tell calibre that anything has changed ,so calibre still has access.
in case 2, calibre has to ask windows what drives are available when it starts up & is not told about the "removed" drive.
I don't think you have anything to worry about really, you can connect device to PC , transfer books, charge device, take it away and use it...
quit fretting while you are still winning
