Unexpected behavior with Enhanced Input Mapping and UMG menu navigation

I am using UMG to design the main menu for a game prototype. To handle navigation around the menu there are two Widget Blueprints: one for the main menu, and the other for a reusable button.

The core idea works well: After the simulator starts I click Button1. This highlights Button1 and turns it green (focus). Then I press W to “move up” which successfully moves to Button4 and it turns green. (See screenshots below.)

If I continue pressing W the navigation will move up as expected. However, the problem is that when I navigate from Button2 up to Button1 focus does not stay on Button1, and immediately jumps to Button4.

TL;DR: This feature works except that I cannot navigate back to Button1 and stay there. When I go up from Button2 to Button1 the UI jumps to Button4 immediately.

Can someone explain why this happens? I believe the problem is related to Enhanced Input Mapping. The issue only affects the first button on this list in the main menu Designer view (in this case Button1).

  1. PlayerController

  1. Main Menu Widget Blueprint

  1. Button Widget Blueprint (On Focused Received function)

  1. Button Widget Blueprint (Event Graphs)

  1. Input Mapping Context

  1. Simulator (before clicking Button1).

  1. Simulator (after clicking Button1)

  1. Simulator (after pressing W key once)