It has been an issue for a couple of weeks for me, I have already finished hero trials section with all the first heroes available yet I have not been able to claim the rewards from this quest and the final rewards consisting of 3 mascheranos for heroes chronicles chapters. Attached below is the proof of the quest being unclaimed/unfinished while having to finish everything with 6 heroes
Its clearly mentioned 'Unlocks after winning the final rewards with all the first 6 heroes'. So all you need to do is complete 'Hero Trial' with the first 6 heroes.
Note that you can claim the cards without completing the trial with the hero as all you need is 80-100(can't remember on top of my head) hero tokens which can be obtained even by just claiming your daily reward of 10 tokens for 10 days in Hero Academy.
It has become a bit complicated with the launch of Squad B heroes but the fine print is quite clear. It's not a bug and clearly explained by EA_Pulsar and mendozzamagic above mate.
Having said that it would have been great to have a counter as to how many hero trials have been completed mendozzamagic and EA_Pulsar
ALR done that for a lot of times, i finished the hero path for a more than once with all the first batch but problem remains and it is still locked. some players are facing the same issue, its not a matter for the comprehension, it is just literally bugged for some players.
and even before the launch of Squad B heroes, it remains locked even tho I played this mode every day, frustating that it remains and havent been fixed.
you don't just have to play the path though, you have to complete it and claim the reward at the end ...
