Just as an aside, why would stock levels not being zeroed or indeed being zero have any influence on preorders for frames that haven’t been built yet?
The “stock” is just a qty manually assigned to the item (obviously there should be some logic behind it), it won’t be a fully automated amazon warehouse style operation, it’ll be done by hand.
So for example if they knew the next batch would be 50 frames they’d allocate 50 stock to the pre-order, the system will be set up to refuse orders for which there is zero stock so would prevent people being able to order frames that won’t get produced as part of the batch.
The stock system has no concept of whether the item is a preorder frame, physical stock of a frame or a t shirt, they’re just text descriptors.
Of course in the particular case the system appears to have been given 10^z stock so that doesn’t hold.