That sure is more unusual oddity from Trump-world, again.
United States
In the United States, the prefix the Honorable has been used to formally address various officials at the federal and state levels, but it is most commonly used for the President, governors, judges, and members of Congress when formally addressing them.[12] Modifiers such as the Right Honorable or the Most Honorable are not used. The "t" in "the" is not capitalized in the middle of a sentence.[13]
Bumping Ivanka to that level could be seen by Donald as another step up the ladder toward her being seen as suitable to follow in her father's footsteps.
It was Plato who said, “He, O men, is the wisest, who like Socrates, knows that his wisdom is in truth worth nothing”