Why am I not getting badges of courage at the end of a tournament?

In order to start receiving badges of courage at the end of a tournament, you have to participate in tournament stages at first.
Please pay your attention to the bar which appears right after a tournament has started in the right corner of the screen - it shows what you will get for participating in each stage of the tournament.
In total, all participants can earn up to 60 additional badges of courage despite what were the results of a match - defeat or a victory, both results will count towards in the bar.
Once new tournament mechanics was released, it also started requiring participation from each player, so if you don't participate in tournament stages and just skip them, then you will not get a reward at the end of a tournament.
If you didn't receive a reward for a tournament, then it means that you finished up the tournament on last places (10 through15) and didn't initiate even a single battle.
Moreover, the common tournament chest was removed from the game entirely. You may find an updated list of the tournament rewards in the corresponding arena window before the start of a tournament.