Summoners War: Chronicles

I had accepted quest before the field event was live and killed Paghor but did not complete quest.  So I thought I'd wait till the second time he was up and try again, dropping quest and re accepting.  Not really participating in field events, I had no idea I could not do a second time after 1st was completed, but decided to kill again anyway maybe it would complete, but no go.  So guess I'll give up on that quest line.  This is on hive PC version not steam.