New information has come to light suggesting that Lucas never approved Dark Empire for publication:
https://www.reddit.com/r/StarWarsEU/comments/vso18w/lucy_autrey_wilson_creator_director_of_the/
Lucy Wilson, who was in charge of the EU in its early days, says that she approved Dark Empire without talking to Lucas and Lucas wasn’t happy when he found out that a comic with Palpatine surviving in clones was published.