For CardDAV logs, in Terminal type:

defaults write -g ABMigrationLogEnabled -bool YES

defaults write EnableDebug -bool YES

defaults write LogConnectionDetails -bool YES

Then relaunch Contacts and see if you can reproduce the problem.

If so, then attach the following: ~/Library/Containers/

Then disable the logging by typing in Terminal again:

defaults delete -g ABMigrationLogEnabled

defaults delete EnableDebug

defaults delete LogConnectionDetails