Storage Fees included on Market Level
Amazon only applies its storage fees on market level - ie. Europe or North America - so that they are not available for singular marketplaces or products.
You can change to those markets at the top right:
Attributed to Day of Charge - Increase Timeframe to view Storage Fees
The fee will only be linked to the day when Amazon bills the Seller Central account.
If such a day is not included within the selected timeframe, no storage fees would be shown. It basically works like an order for an Amazon service and is thus only connected to that specific day.