Editable Text doesn't reflect changes after having its style changed at run time. The style is changed within the Editable Text correctly, but those changes aren't reflected.
The Style of the text has changed to match the new style, or any next text that is enter reflects the style change.
The Style does not change.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-147566 in the post.