I've encountered similar. I had been throwing them ingots and they'd pocket the item and run away as they were dropping their item in exchange for it, but it seemed to be hit and miss if they would throw an item down. It seems like the Bedrock Edition skips the animation they have where they inspect the item and goes immediately to pocketing it, throwing you the item in exchange, and running away. If it seems like they're not dropping items, check around where they were standing, because it seems to happen instantly.
I didn't know they could equip things, but dropping their items it seems like not every Piglin has anything in their inventory, or as you've mentioned maybe some of them don't even have one.
I've encountered similar. I had been throwing them ingots and they'd pocket the item and run away as they were dropping their item in exchange for it, but it seemed to be hit and miss if they would throw an item down. It seems like the Bedrock Edition skips the animation they have where they inspect the item and goes immediately to pocketing it, throwing you the item in exchange, and running away. If it seems like they're not dropping items, check around where they were standing, because it seems to happen instantly.
I didn't know they could equip things, but dropping their items it seems like not every Piglin has anything in their inventory, or as you've mentioned maybe some of them don't even have one.