Thank you.
I tried using Get All Widgets of Class with UserWidget, and the result showed a length of 1.
At first, I wasn’t sure what it was, but it turned out to be the crosshair widget that is always on screen.
So I’ve started to think that the issue might not be with the UI, but rather with the character’s movement or control settings.
The image below shows the Blueprint where, when a conversation starts, it disables movement and camera input.
Then, once the conversation ends, the bottom nodes are executed to re-enable movement and camera control.