Tracker's Knife charge isn't based on visiting the shop

With the way the charge refill system works, it is very possible to buy the item with zero charges intact.

I've walked to the edge of the fountain a few times, then bought Tracker's Knife, and had it without any cahrges.

I've bought it in a closer proximity to the shop, and it did come with charges.

I then tried buying it at the edge of the fountain, it came with no charges, so I walked closer to the shop and the charges appeared.

It would appear that the charges of the tracker's knife are based on how close you are to the shop.