Description of problem:
During the upgrade of package tcpdump:
useradd[3979]: failed adding user 'tcpdump', exit code: 9
...

But user 'tcpdump' already exists, so this is just harmless warning because the 
user is attempted to be created unconditionally. Please put

"getent passwd tcpdump &>/dev/null || "

before the creation attempt.

Version-Release number of selected component (if applicable):
tcpdump-4.9.2-7.fc30.x86_64