Unable to short a stock even though API reports a stock is easy to borrow and shortable

I am using
alpacaTradingClient.ListAssetsAsync(new AssetsRequest() { AssetStatus = AssetStatus.Active }) and then filtering based on if it is marked as shortable and easy to borrow. However I received the message today on a stock that it could not be sold short when my app tried to place the trade. The stock was “ALZN”. This is not the first time this has happened, but since it is a reoccurance I thought I would reach out to better understand what is happening. I pull a fresh list of shortable stocks before trying to short also.