Keyboard and mouse navigation/selection of items fails, seems to be "duplicate item" related, unsure

This is a weird one, I say beforehand. Probably you will need me to show it with a screencast or something, but since sensitive information, I will do that after determining a safe place/safe tool to do that with and only if needed.

The issue seems to be a "duplicate items" problem, but even after changing one of the items, I cannot select the other item.

Now, we have A LOT of legacy items in our keychain, we have been using 1Password since forever (version 3), so it might be related to that, I don't really know, but I do have suspicions.

The symptoms:

I noticed first that some logins cannot be navigated through with keyboard.
I would open the popup using the keyboard shortcut, then try to browse through the available logins, and the selection-highlight (the "cursor") would get stuck at a certain point (as in, not able to move further down) but I could co back up. I could go left to the categories, I could go right to details, but not down. This does NOT happen in the 1Password main view.

Trying to use the mouse instead gives the same issues; when clicking on the "second" of the duplicate items, the selection jumps back to the first one.

Trying to explain a little more, with a real example:

I have two items, one is in my primary(work) vault, the other in my private vault.
both items are a login to a router (we no longer have, but the login is still listed) and so both logins have the same data:
title: 192.168.123.254
url: http://192.168.123.254/login.html
user: admin
password: (fake) 123456
Both items are identical because they once existed in two keychains, because 1Password hasn't always been multi-vault.

When browsing the logins in the 1P popup, I can go to the first entry of these two, but not the second. When I select the second one with the mouse, the first one gets selected instead.

Now when I edit the first one (the only one I can edit) and add a hyphen at the title, so it becomes 192.168.123.254-, it is now (alphabetically correctly) listed as second item of the two. I now can select the first (unedited) item, but not the second (recently edited). I can keyboard-navigate to the first one, but never the second.

Hope this gives a good idea of the issue.

Now, you might have questions, and I have answers :)

My private keychain is in origin a disk-to-disk copy of the then pre-existing work keychain (copied sometime back in 2008).
Assumptions we could make from this are

• the items are real duplicates, not just two items with the same data
• the items have the identical internal "serial number"

We have many items that are affected by this, not just this one example. Some have identical data and are easy to spot, others have been edited in the past in one keychain, and are untouched in the other keychain, and they still exhibit the same symptoms.

They are always in different vaults, never in the same vault, which kind of proves (to me, at least) the theory of the problem being caused or having to do with the internal identifier. Why this does not affect the main view and only the popup view surprises me, but that's what happens.

I know the data (content) is 90% of the problem, and perhaps the only answer would be to just cleanup the mess, but being a developer, I would still want to fix the issue ;)

Final note:

I've set-up a test on Windows; this issue does not appear to be present in the Windows version.

Thanks for your time and effort to read all this ^^.

Remon.

1Password Version: 7.0.2
Extension Version: 4.7.1
OS Version: 10.13.3
Sync Type: DropBox + 1PassWord Cloud