Kobo: Book not 'On Device' until after Kobo import?

This isn't how I first noticed the issue, but it is the easiest to replicate. Here's what I'm seeing:

1. Connect Kobo via USB.
2. Send new epub (not kepub) book from Calibre to Kobo over USB.
3. Book shows 'Main' in 'On Device' column in Library view.
4. Quit Calibre -- without disconnecting Kobo.
5. Start Calibre -- wait for device to be recognized.
6. Book does NOT shows anything in 'On Device' column, nor in the Device view.

Following these steps, I can get everything back to expected normal:

1. Send book to Kobo again
2. Eject Kobo.
3. Wait for Kobo 'import books' to run and new book to appear in Kobo list.
4. Reconnect Kobo.
5. Book does show 'Main' in 'On Device' column and appear in Device view with 'In Library'. Normality achieved.

But wait, I can make it worse! I can instead do (from the end of the first list above):

1. Eject Kobo without sending book again
2. Wait for Kobo 'import books' to run and new book to appear in Kobo list
3. Reconnect Kobo
4. Book does not shows anything in 'On Device' column. But there is now a book with that name(after plugboard) in the Device view showing nothing for 'In Library'.

Why it matters to me:

Since I'm using KOReader, not the native Kobo app, I'm not running Kobo's import regularly. So new books are on the device, but are invisible to Calibre.


I'm using Calibre 8.4 in Win10 and a new Kobo Clara Colour. I've attached shots of my KoboTouch driver config--I turned off everything I thought would make a difference.

Attached Thumbnails