I thought you got one trophy for defeating someone at an equal/lower PVP rank, and two trophies for defeating someone higher.
Here is a pair of screenshots that suggests I am mistaken.
In this image I have a lower rank than my opponent, but I am only offered one trophy.
And indeed, that is how many trophies I received. I unfortunately don’t know if my guild was actually awarded two trophies; the counter went up by more than two during the fight so I can’t say how many are mine vs my guildmates’.
Was this a revenge battle? If so then the opponent was a lower/equal rank when they fought you, but appear higher when you finally fought them back.
If not then I’ve no clue what that’s about.
It was a revenge, but I feel like I have seen revenge battles go from 1 to 2 trophies when my target was more active than I was.
You can see from the initial screenshot that you can win 1 trophy.
What I think happens is that while the opposing player level is current in the display, you’re fighting the Revenge battle at whatever level he fought you at, which was equal or higher than yours at the time. That’s why you can only win one trophy there.
I’ve seen it go from 2 to 1, but I’ve never seen it go from 1 to 2.
Having said that, the levels always matched up and made sense when that happened.