The placard shown on your player profile is the rank you earned during the previous week's Rift season. Matchmaking is not based on this rank, but on your current Rift score. As it happens, players in every rank from Bronze 4 through Gold 3 (and even most of Gold 2) get reset to 1000 score at the start of the season. Thus, it is very common for players in all of those brackets to get matched up against each other, at least until the players in the upper end of that range have worked their way back over 1100 points.
As an extreme example going the other direction, I didn't have time to Rift at all during the August 8-14 season, so my rank reset to Rookie. My last attack during the August 15-21 season beat a player in Diamond 4.