Piglins get mad when you open certain containers since they assume you are stealing.
You can't steal anything from an ender chest though, so this seems odd.
Piglins attack player with gold armor
Piglins attack at Ender Chest being opened
Piglins aggro when destroying my ender chest
Piglins attack when you open an ender chest near them
Opening Enderchests Alert Piglins
Ender Chest with gold trigger Piglin attack
Piglins agro players when they open shulker boxes and ender chests.
Piglins attack player regardless of storage system
Piglins are not angered in some gold/chest-related circumstances
Piglins attack players if a chest placed by any player is opened
Opening/breaking a shulker box near piglins will cause them to attack you