The screencap looks like you've selected "Defending Inferno Staff" (looking at the item's trait which is highlighted and stone enlarged) which that character already knows...
Is Uncle John's band calling you? Do you daydream about Sugar Magnolias? Is your favorite sunflower a China Cat? Tired of Truckin' alone to Terrapin Station? If so, share some Space with other hippies & deadheads in the guild Sunshine Daydream! Send a message in game (PC-NA) to Kaibeth for your invitation.
If you haven't already tried it. Turn off all of your ad-ons and see what happens. If that fixes it, turn them back on one at a time until you find the culprit.
Are they locked? I had the same problem and anything in the bank that is locked won't show up. Reread op and was not the issue. My thing was I knew I had a Nirnhoned item in the bank and it wasn't showing up in the research tab. Forgot that I had locked them as they were white items and I didn't want to accidentally sell them.