Keep in mind that everything happening in the game is updating back and forth to the Destiny data servers, as well as potentially anyone else on the map. This includes your loadout, armor, etc. Therefore, any time you open your character menu, it has to sync all the data with the server before displaying it. It is doing this amongst all other data that is transferring back and forth as well, so if you are in a fire fight, it is going to take longer. While in orbit, it should be better, but it still has to sync so there will be a short pause before everything shows up on screen.

Just to confirm what the issue is: You're saying that when you open your character screen to manage your inventory, that takes a significant time to load? If so: I also have been having this issue occasionally. Biggest thing I've done to acclimate with the slowness, is to simply open my menu when there are not many things going on. For some reason, if I am in a popular public event, a patrol area with tons of players and enemies, or even during the loading time in and out of crucible or strikes, I experience this slowness. Another possible fix, though it may be a shot in the dark, would be to power cycle your console by disconnecting your power cord. This will refresh general connectivity and may knock something loose. I play on a dual monitor setup and utilize my second screen for Xbox display. On the other one, I use [url=https://destinyitemmanager.com/]Destiny Item Manager[/url] on chrome. It's a great web app that helps manage my three character's inventory amd saves me a lot of vault trips. Hope this info helps!