LibreOffice windows with search bar open stay on top despite Alt-TAB

In LibreOffice Calc or Writer, doing Ctrl-F to search/find and then Alt-Tab to switch application does switch the focus as expected, however the LO window stays on top.

This has been reported to the LO community, but it seems that it isn't reproducible on other window managers/desktop environments: https://bugs.documentfoundation.org/show_bug.cgi?id=156232 (duplicate: https://bugs.documentfoundation.org/show_bug.cgi?id=166590).

My setup: XFCE 4.20, GTK 3.24.38, X11 LibreOffice 25.2.3.2 (X86_64) / LibreOffice Community Debian package version: 4:25.2.3-2~bpo12+1