Comment 3 for bug 1845314

2. Why this is happening?

First of all, the udisks2 installation fails because the postinst script fails. Inspecting the postinst script of udisks2, we can see these lines:

if [ "$1" = "configure" ]; then
    # we ship udev rules, so trigger an update
    udevadm trigger --subsystem-match=block --action=change
fi

That udevadm command fails, i.e. ends with non-zero status with systemd >= 243. This new different behaviour of udevadm makes the postinst script fail, and that makes the package installation fail.

While I didn't git bisect the thing, reading the systemd git history makes me believe that the specific commit which produced this new behaviour could be this one:
https://github.com/systemd/systemd/commit/0584b17a8c7d17649aef9f06a8aee304dc80eb7e