I need to tell you that this bug is real. Please, read this entirely.
There’s also a few very similar things that’s probably related to the same issue, described above.
I just collected the Invasion rewards, up to Stage 4 only, but the button or option Collect did not grey out, was not disabled, so I was able to click on it repeatedly. No extra rewards were given, but this just confirms the issue is real and more widespread (Pet Rescue Event /Invasion/Bounty?/Raid?Stage Rewards/Shop Tiers/etc.?).
This issue can also happen sometimes in the Troop selection screen.
I ascended a Card from Legendary status to Mythic, but nothing happened. The card was still at Legendary status. I had to restart the game so that it was at Mythic status so that I was able to upgrade it to Level 20.
I also tested the Disenchantment feature - selling excess troop cards.
I sold a few Dooms, but I never received any extra souls (5), nor did the number of that troop decrease. I think it counted later after a game restart.
There was also no message to indicate that there was some sort of a problem, because it was not a connection issue. So, again, only the game restart then showed the proper number of disenchanted troops - Dooms.
This issue can happen in the Pet Rescue screen, where a Pet battle that was just completed, did not count. Same goes for the Shop Tiers. I bought Tier I, but it was not properly registered in the Pet Shop.
Had to restart to see theTier I bought, etc.
Of course, the only thing that fixed this was a complete restart of the game. And no, connection wasn’t the issue here. That’s the first thing I checked.
I think that this issue started with 4.3 update, not before that.