How much does a Bag of Holding weigh when it is infused by an artificer from a normal backpack (using the Replicate Magic Item infusion)?

Question

I searched for an answer to this question, but could not find one.

The "Infusing an Item" section of the artificer's Infuse Item feature description states:

Whenever you finish a long rest, you can touch a nonmagical object and imbue it with one of your artificer infusions, turning it into a magic item.

Once my artificer achieved the appropriate level, he chose the Replicate Magic Item infusion for a Bag of Holding. This he fashioned from his existing backpack, which has a PHB weight of 5 lbs. However, a Bag of Holding normally weighs 15 lbs.

Which weight do I use for my encumbrance considerations: 5 lbs. or 15 lbs.?

Answer 1

The (infused) Bag of Holding weighs as much as a (non-infused) Bag of Holding

When you use the Replicate Magic Item infusion, you are... replicating a magic item:

Using this infusion, you replicate a particular magic item.

This is reinforced by the description of the Infuse Item feature (emphasis added):

At 2nd level, you gain the ability to imbue mundane items with certain magical infusions. The magic items you create with this feature are effectively prototypes of permanent items. [...] you can touch a non-magical object and imbue it with one of your artificer infusions, turning it into a magic item.

So, the backpack that was infused to create a Bag of Holding is literally a Bag of Holding as long as it remains infused. Unless otherwise noted, the properties of the item are identical to the non-infusion-based version of the magic item being replicated. That includes the item's weight.