3D Navigate Level Selector Inconsistency

When we open our CATIA data in the 3D Navigate window, in Product Explore, we are finding inconsistencies regarding the level selector.

On some models, we are able to click a part on the screen, and only that part becomes highlighted, and we can then scroll through the level selector to select whichever level of the product structure we wish. Also, the product is highlighted in the tree in the Product Structure Explore window. This is the normal behaviour we'd expect to see.

But on other models, the whole product is selected when we click on a child part of it, and instead of the level selector, the X "Close" symbol appears instead, and the item selected is not highlighted in the tree. Sometimes we even see this in the same model, where some child parts can be selected individually, but selecting others only result in the whole product being selected.

Is this something anyone else has seen? Any solutions? We're using V5, and we're on 3DX 2023x, managing the CATIA files as XCAD objects.