I have the same issue. Before during any other faction challenge the repeatable quests counted towards the contracts. This time as you stated it does not after completing the 4th quest. Wrote a ticket today (so no reply yet) so lets see what the support thinks.
I very much hope it is a bug as I wanted to complete the full set of contracts supporting a faction. I chose twice in a row Monsters for this reason but if it is intended then I lost the opportunity to get titles for each faction.