Bug happened when saving an Entries field, the selected entries are there twice.

Description

A weird bug happened when saving an Entries field.

Steps to reproduce

On my Catalog section, under a Entries field, I select 2 entries (from a Product (structure section)). Save. And when the page reload, each Products are there 2 times. I was thinking about a UI issue, but if a query this specific entry I can see 4 ids (2 x 2).

To see it in action: https://recordit.co/FYxYyMGIUW

Notes:

• I try with one, two and more Products, same issue. If I delete the dups and save back, they came back again.
• I try with a fresh new Catalog, the same issue happened. But if I try with a fresh Products, the issue dont happen.

I then try to resave all the entries (craft cli), a ./craft utils/repair/section-structure product, the issue is still there.

Any way to get that fix? I got 400+ products create by the client, so start over isnt a solution.

Additional info

• Craft version: 3.5.15
• PHP version: 7.3.24
• Database driver & version: MySQL 10.1.46

Start with the Catalog and Products reproduction steps, then inspect the Craft CLI entry point ./craft utils/repair/section-structure product and compare the saved entry IDs before and after reload. Done means selected Products persist once in a fresh Catalog and existing duplicated relationships can be repaired without recreating the 400+ products.