All Photos > By Date sidebar subsection collapses as Lightroom is loading

Routinely when I open Lightroom and hear my external drive cranking as some previews are likely being cached, if I use the All Photos sidebar to navigate to a specific By Date year and month after a few seconds the sidebar reloads itself and collapses completely, losing my current place.

Even clicking on a picture that is currently displayed in the grid doesn't re-open the year and month I had selected. This points to a state bug when previews are being generated. Some sort of load completion event is triggering a full sidebar reload regardless of current user selection.

It would be really nice if you could address this bug. It's been occuring for several minor releases at least. I'm sure it's particularly noticeable on larger catalogs.