Do you have a source for this? If I have ever heard this hypothesis before it has long been forgotten.
The posthumously published edition of this impromptu was prepared by one of his students, Fontana. It is quite different to the actual autograph. Some notable differences are that it is simplified and more technically accessible (too easy, even for Chopin to write); inner voices are altered, notes are deleted, expressive markings altered, et al. Any pianist who is well-familiarized with Chopin's musical and technical oeuvre will note that the Fontana edition is not what Chopin would have written - it doesn't feel genuine nor does it sound genuine.Most pianist play the Fontana edition because it was the first and most widely available and it is easier to play. Also, most pianists are unaware that they are using the Fontana edition as they are ignorant of any other edition.Fontana edited most of Chopin's works that were published posthumously including his Op.69 Waltzes, which also differ from the autograph. The B minor Waltz (of this same opus) adds an inner voice which adds to the texture and actually sounds better than the autograph.The Autogrpah score was composed for Madame la Baronne d'Este.
I've even heard he stole the theme from someone else, and that's why he hated it.
One might wonder the circumstances of the FI's composition. Was Chopin randomly improvising during a time when he was studying the Moonlight? Maybe he needed a "lick" in C# minor going downwards and this Beethoven thing was in his fingers.
Guys did you know that chopin regretted in composong this piece???!!!!!!! ???actually before he died he told/asked his student to burn this piece but his student did not burn it...Well, i dont know the reasons behind why chopin hated this impromptu (which really sounds beautiful) hahahaah......... anyway the inbetween notes are so hard to play...!!!!!!!!!!!