This seems to be a pretty consistent issue in mods with effects that retrigger jokers, but I figured I would mention it because it scales up pretty severely here. When you have the Brass Joker copy a held-in-hand retrigger joker (I'm using Marigold for this example), everything seems fine for held-in-hand effects when a hand is played. However, for end-of-round effects, like the effect of gold cards or marigold cards, the joker retriggers proliferate in a very strange way. For every joker retrigger caused by the Brass Joker, you get one card retrigger per joker retrigger, plus the Marigold retrigger. For example. with a Brass Joker at 1, you get:

• Original trigger
• Two triggers from Marigold
• One trigger when the Brass Joker causes Marigold to retrigger
• Another two triggers from Marigold

However, if we scale the brass joker up to 3, it goes as follows:

• Original trigger
• Two triggers from Marigold
• Three triggers when the Brass Joker causes Marigold to retrigger the first time
• Another two triggers from Marigold
• Three triggers when the Brass Joker causes Marigold to retrigger the second time
• Yet another two triggers from Marigold
• Three triggers when the Brass Joker causes Marigold to retrigger the third time
• Still another two triggers from Marigold

This gets out of hand pretty quickly, especially if you bring in a Blueprint or a Brainstorm, which seem to retrigger the same card that Brass Joker is targeting instead of the card to their respective right. Not really related to the issue at hand, but I feel like they should probably be incompatible with Brass Joker.