See Item #5:
2-10 Updates and Investigations | EA Forums - 13175351
[Marked as solution for player visibility only - CM]
Many in my guild bragged and shared screenshots of receiving all three types of Signals in their inboxes as rewards for reaching a certain position in the Colosseum leaderboard. But for some reason, my account didn't receive any such rewards. Only Era Currency for converting materials. I'd like to know why.
Tulak Hord
ID: 928-844-549
It has been acknowledged here:
https://forums.ea.com/blog/swgoh-game-info-hub-en/2-10-updates-and-investigations/13175351
