Unmounting a drive from the dock does not take place no more

I’m having a situation when unmounting a 2nd drive from the dock with mouse does not take place no more. The 2nd drive is with LUKS. I have a feeling that this (unmounting from the dock with mouse) took place earlier correctly. Now the 2nd drive logo disappear from the dock, but it remains mounted and opens from Nautilus without requiring LUKS password.

Now in order to unmount the 2nd drive I have to do it from Nautilus with mouse.

Please inform if this kind of unmounting (only from Nautilus) is new normal and correct action expected from the end user or can I do something in order to make this unmounting of a 2nd ( or 3rd etc…) drive to happen also from the dock.