Resetting the store while looking at it

Just ran into an annoying thing where I was checking out the store and noticed two items I was going to buy, but by the time I made the decision to do that, the store had reset and the buy buttons were darkened out on those items. I exited and went back in to the store and it had reset and showed 59 minutes until next reset.

In short, if you have the list of items up, you should still be able to purchase them even if it reset while you were looking at it. Both of the weapons I wanted to buy were no longer available for me in the new batch, which is irritating.