A couple arena problems and gem chest question

Was playing arena and when I picked one of my cards I picked a goblin with 9 attack from magic, but when I check in match it is only 7.
Also, if I back out of a match and not lose, it counts as a loss.
Do these things happen to anyone else?
Also, does changing the difficulty change the end reward amount?

Anybody else have this happen to them?

I have almost 1000 gems and was thinking on using them on the chests. But what chest should I use, as there are 2 chests that use gems.

Also, while I am here I will ask another question.
How is it determined how much gold you get in a match, especially PvP?
I know you get armor to increase the gold, but playing PvP for example, sometimes I get over 2000, sometimes I get under 2000.
What determines the starting gold amount when playing PvP?
Does match length play a part?

About your Arena questions, the Goblin problem is a bug. It can be annoying when one is not familiar with their actual skill levels for Arena.

If you retreat from battle, it does count as a loss. This is normal.

Yes, changing the difficulty will yield greater rewards if you win 8 battles. Do not be surprise how difficult it is for you to achieve that.

About the gems, you can open Gem Chests and Event Chests. You can also buy souls, gold, and armor from the shop. I would recommend spending your gems on Event chests.

Maybe someone else can answer your PvP questions better than I can. Only thing that matters is to win those trophies for your guild. Ranking up the leagues will earn you bonus gold when you log in daily.

Thanks for that.

Yeah I know, was just curious how it works out how much gold each opponent starts with and your end gold result.