I had played a couple matches of br, and those chests with counters that tell me to do something (example: get assists in any PvP match) are bugged. My assists didn’t count. (Rip my time for playing 10 br matches)
However, I have issues only with br .Other PvP gamemode work just fine.
(Sorry for my bad english, english is not my mother tongue : p)
They probably have counted, but there is a problem right now. For now, just close Vainglory and re-open it, then tap to the quest tab. They should give you the chest now.
tap on your ig name, close the window and look on the chest
Restart the app. Then it should be fixed.
There is a major update lag that the developers have been informed about.
All of them are bugged in mine