Bug Report: Missing Add Block Button

We have dozens of websites running WP 6.4.3. Only 3 of them are using Widget Options 4.0.1, and in all three of those sites, when editing pages, the “Add block” button (the plus sign) is missing when trying to add a new block between existing blocks.

On other sites, when I want to add a block between existing blocks, if I move my cursor between the blocks, the plus sign pops up. But on these three sites, it does not. When I disable the Widget Options plugin, the plus sign does pop up when it is supposed to.

We’re using Genesis 3.5.0 and Breakthrough Pro 1.3.1 on these sites, but when I switch the theme to Twenty Twenty-Four 1.0, I have the same problem. So far, the only thing that fixes the problem is deactivating Widget Options. I even tried deactivating all the plugins EXCEPT Widget Options, and I still encountered the problem.