Why does apt only remove some automatically installed packages?

On a Raspberry Pi I installed CUPS. This is from /var/log/apt/hostory.log: ` Start-Date: 2025-07-18 01:05:00 Install: libieee1284-3:armhf (0.2.11-14, automatic), cups-filters:armhf (1.28.7-1+deb11u3, automatic), libpaper1:armhf (1.1.28, automatic), libsnmp-base:armhf (5.9+dfsg-4+deb11u1, automatic), libjbig2dec0:armhf (0.19-2, automatic), libidn11:armhf (1.33-3, automatic), sane-utils:armhf (1.0.31-4.1, automatic), libgphoto2-l10n:armhf (2.5.27-1, automatic), acl:armhf (2.2.53-10, automatic), libsnmp40:armhf (5.9+dfsg-4+deb11u1, automatic), ssl-cert:armhf (1.1.0+nmu1, automatic), cups-common:armhf (2.3.3op2-3+deb11u9, automatic), libgusb2:armhf (0.3.5-1, automatic), usb.ids:armhf (2024.07.04-0+deb11u1, automatic), libijs-0.35:armhf (0.35-15, automatic), liblouis20:armhf (3.16.0-1, automatic), cups-client:armhf (2.3.3op2-3+deb11u9, automatic), cups-ppdc:armhf (2.3.3op2-3+deb11u9, automatic), libcolorhug2:armhf (1.4.5-3, automatic), cups-daemon:armhf (2.3.3op2-3+deb11u9, automatic), update-inetd:armhf (4.51, automatic), colord:armhf (1.4.5-3, automatic), libfontembed1:armhf (1.28.7-1+deb11u3, automatic), liblouis-data:armhf (3.16.0-1, automatic), libqpdf28:armhf (10.1.0-1, automatic), libgs9-common:armhf (9.53.3~dfsg-7+deb11u10, automatic), libpoppler-cpp0v5:armhf (20.09.0-3.1+deb11u2, automatic), poppler-data:armhf (0.4.10-1, automatic), fonts-noto-mono:armhf (20201225-1, automatic), cups-filters-core-drivers:armhf (1.28.7-1+deb11u3, automatic), poppler-utils:armhf (20.09.0-3.1+deb11u2, automatic), cups-ipp-utils:armhf (2.3.3op2-3+deb11u9, automatic), ghostscript:armhf (9.53.3~dfsg-7+deb11u10, automatic), fonts-urw-base35:armhf (20200910-1, automatic), libgphoto2-port12:armhf (2.5.27-1, automatic), libpoppler-glib8:armhf (20.09.0-3.1+deb11u2, automatic), ipp-usb:armhf (0.9.17-3, automatic), libsane-common:armhf (1.0.31-4.1, automatic), liblouisutdml-bin:armhf (2.9.0-1, automatic), libpoppler102:armhf (20.09.0-3.1+deb11u2, automatic), libpaper-utils:armhf (1.1.28, automatic), cups-core-drivers:armhf (2.3.3op2-3+deb11u9, automatic), liblouisutdml-data:armhf (2.9.0-1, automatic), bc:armhf (1.07.1-2+b1, automatic), colord-data:armhf (1.4.5-3, automatic), libgphoto2-6:armhf (2.5.27-1, automatic), cups:armhf (2.3.3op2-3+deb11u9), libsane1:armhf (1.0.31-4.1, automatic), libgs9:armhf (9.53.3~dfsg-7+deb11u10, automatic), liblouisutdml9:armhf (2.9.0-1, automatic), fonts-droid-fallback:armhf (1:6.0.1r16-1.1, automatic), cups-server-common:armhf (2.3.3op2-3+deb11u9, automatic), libcupsfilters1:armhf (1.28.7-1+deb11u3, automatic) Upgrade: libcups2:armhf (2.3.3op2-3+deb11u6, 2.3.3op2-3+deb11u9) End-Date: 2025-07-18 01:07:52 ` Then I uninstalled it again (by selecting cups in aptitude and pressing _). As you can see, some of the automatically installed packages were removed, but not all of them: ` Start-Date: 2025-07-18 01:49:18 Remove: cups-filters:armhf (1.28.7-1+deb11u3), liblouis20:armhf (3.16.0-1), cups-client:armhf (2.3.3op2-3+deb11u9), cups-ppdc:armhf (2.3.3op2-3+deb11u9), cups-daemon:armhf (2.3.3op2-3+deb11u9), libfontembed1:armhf (1.28.7-1+deb11u3), liblouis-data:armhf (3.16.0-1), libqpdf28:armhf (10.1.0-1), libpoppler-cpp0v5:armhf (20.09.0-3.1+deb11u2), cups-filters-core-drivers:armhf (1.28.7-1+deb11u3), cups-ipp-utils:armhf (2.3.3op2-3+deb11u9), liblouisutdml-bin:armhf (2.9.0-1), cups-core-drivers:armhf (2.3.3op2-3+deb11u9), liblouisutdml-data:armhf (2.9.0-1), bc:armhf (1.07.1-2+b1), liblouisutdml9:armhf (2.9.0-1), cups-server-common:armhf (2.3.3op2-3+deb11u9), libcupsfilters1:armhf (1.28.7-1+deb11u3) Purge: cups-common:armhf (2.3.3op2-3+deb11u9), cups:armhf (2.3.3op2-3+deb11u9) End-Date: 2025-07-18 01:49:41 ` Why the difference?