When I challenge my friend to Friendly Brawl, despite showing as a friendly brawl challenge on my client, on theirs it registers as 60-card. When they challenge me to friendly brawl, I get 60-card. Further, whoever issues the challenge and sees it as brawl will be asked to choose a brawl-valid deck, but it will not validate (presumably, since they would actually need a 60-card deck instead of a brawl deck).
When I challenge my friend to Friendly Brawl, despite showing as a friendly brawl challenge on my client, on theirs it registers as 60-card. When they challenge me to friendly brawl, I get 60-card. Further, whoever issues the challenge and sees it as brawl will be asked to choose a brawl-valid deck, but it will not validate (presumably, since they would actually need a 60-card deck instead of a brawl deck).