Platform, device version and operating system
What you were expecting to happen, and what actually happened
Invasion rewards require too few tower kills. It looks like the intended number should actually be the sum of all preceding numbers, e.g. kills required for reward 11 should be the kills for reward 1 to 11 instead of 300.
How often does this happen? When did it begin happening?
This weeks Invasion. It’s actually the reverse bug of the previous Invasion, were totals for kills were summed up twice around.
Steps to make it happen again
Look at the Invasion reward screen, do the math.
It’s probably not a good idea to retrofit numbers with most rewards already having been handed out. Call it an easy week, fix the numbers for the next Invasion.