At first I though I was hacked, a few minutes later I tried playing with the category buttons and it returned all of my items.

To give you an idea what happened, I just came back logging in to the game, I noticed half of my items were missing including Locks, seeds, crystals, set, blocks, and baits. I was shocked on what to do, and I somehow tried to play the category buttons and it gave me back the items.

It might be a UI glitch hiding the items because of the categories. It gave me a shock, the backpack is half empty not showing any of my missing items unless you play with the buttons.

I might be able to find the solution, but what if this glitch occurs to other players? They might panick from this kind of situation.