Changing UMG Navigation rules at runtime breaks keyboard focus control

Hi there.

I have a list of buttons.

When I view this list of buttons, some of them need to be culled, so I set them to collapsed.

I then need to rebuild the navigation rules for the buttons, as these are used to ensure keyboard and controller focus runs smoothly.

So, for each button left in the list, I re-calculate the up/prev and down/next rules and set them.

However, when using a controller/keyboard, I am now unable to use this navigation. (4 buttons, 2 culled, 2 buttons left in list, keyboard focus on top one, pressing down does not transfer focus)

What is going on here?