As a security conscious person I setup my OpenPGP keys with a passphrase, however on OpenSUSE Leap 15 this causes a login prompt to appear that delays the network connection from initiating. The same issue also blocks software updates and means a browser restart due to DNS cache stopping connections to websites. This is fairly annoying.
It turns out that this can be fixed by sharing the network connection via Connections > open the connection > General Configuration > All users may connect to this network. This causes NetworkManager to cache the required authorization tokens (this is my understanding).
Note that other software such as Kontact might set a daemon to startup by default, causing the same prompt. This can be unticked in its settings.
If everything else fails, then you could remove the passphrase for the PGP key but this is not recommended as this means someone can take on your identity should your key be exposed for any reason.