Maverick Artificer — Can Arcane Prototypes Be Stockpiled Between Long Rests? (RAW)

I'm looking for some insight into the RAW interpretation of the Maverick Artificer's Level 3 feature, Arcane Prototype, from Eberron: Forge of the Artificer.

The feature states:

"When you finish a Long Rest, you can create a prototype if you have Tinker's Tools in hand."

It also states:

"When you create a prototype, choose a spell from the Artificer, Cleric, or Wizard spell list. This expends a number of Arcane Charges equal to the level of the spell..."

The table lists a Max Number of Prototypes for each Artificer level, alongside the maximum spell level and number of Arcane Charges. For example, a level 9 Artificer can create up to 3 prototypes at the end of a Long Rest.

The feature also says that when a prototype's spell is cast, the prototype crumbles to dust unless the Artificer chooses to preserve it by expending a spell slot equal to the spell's level.

My question is: What, if anything, prevents an Artificer from stockpiling unused prototypes over multiple days?

As far as I can tell, the feature limits how many prototypes you can create at the end of a Long Rest, but it doesn't explicitly state that existing prototypes disappear when you finish another Long Rest. Nor does it explicitly say that the maximum number in the table is a limit on the total number of prototypes you can possess.

For example, could a level 9 Maverick create three prototypes on Monday, leave them unused, then create three more on Tuesday, and continue accumulating prototypes as long as they aren't used?

There is nothing in the feature that prevents it. It looks like the intention of the feature is that they would last until your next Long Rest, but there is no language in feature to reflect that.

Quote from Dratomae >>

I'm looking for some insight into the RAW interpretation of the Maverick Artificer's Level 3 feature, Arcane Prototype, from Eberron: Forge of the Artificer. 

Just for the record, Maverick is actually a third-party subclass from Exploring Eberron, not part of Eberron: Forge of the Artificer or any other official content.

I mention this because this specific issue is fairly typical of third-party content that gets published on D&D Beyond; third-party sources often aren't edited as well as official WotC stuff and frequently have issues like this where it seems like the authors were making an assumption that didn't actually get written down anywhere.