Since I updated from FC29 to FC30 my desktop and laptop freeze at the plasma splash screen during re-login. 1. This only happens after a logout from the plasma session. It does not happen after a fresh reboot. 2. Logout works fine. BUT after a logout and at sddm screen if you open a terminal via ctrl-alt-f2 and check if processes for the logged out user are running you see many processes (not kde ones). This includes systemd. 3. If one kills those processes then re-login happens normally.
You may want to consider setting in /etc/systemd/logind.conf KillUserProcesses=yes to ensure session processes do not linger after logout.
Fedora 28 changed to end-of-life (EOL) status on 2019-05-28. Fedora 28 is no longer maintained, which means that it will not receive any further security or bug fix updates. As a result we are closing this bug. If you can reproduce this bug against a currently maintained version of Fedora please feel free to reopen this bug against that version. If you are unable to reopen this bug, please file a new report against the current release. If you experience problems, please add a comment to this bug. Thank you for reporting this bug and we are sorry it could not be fixed.