Basically, recently I learned that some servers don't send data packet to clients pertaining to items inside bundles. This is on purpose to reduce lag. Such as the screenshots below. As you can see, I start with empty bundle and then add items and then I place it in inventory but it doesn't display what items are in there and shows full even though it has 57 items. This also effects the chesttracker mod as those items aren't tracked any longer. This server shown here is 9b9t.com