Piglins keep or "steal" the gold when I try to barter

So when I try to barter with a Piglin, instead of giving me something in return, they just keep it, or should I say "steal" it instead of giving something in return. Also, I have gamerule mobGriefing on. I tried it with a stack of ingots and they "stole" all of my stack. I don't know if this is normal or not, but how can I solve this problem?