Input field loses focus in built application

In my current project I have a 3D environment containing a UI widget with a text input. This text input is automatically focused upon and all other input is disabled (no camera interaction, etc).

When running in editor this works absolutely fine, but after building to a Windows application, the text field doesn’t seem to want to know. I’ve tried pushing focus to it from the widget blueprint itself on creation, as well as after a set time, and also the level blueprint on load. Again, all these methods work in the editor but the built application just doesn’t seem to like it. Even enabling mouse input will not let me click in the text field to focus on it.

Any suggestions?