Hi Ted,
Given your huge output of improvs, I'm not at all surprised that you would recall a similarity as you describe here. The notes spanning an octave have, over the centuries, provided virtually infinite combinations to form melodies and accompaniment. Yet, there are occasionally those moments when, for example, we hear a vignette within a composer's music and say "Hey, where did I hear that before!?" And then sometimes when it dawns on us, we look and find the similar passages, and often check to see who's piece was published first. Sometimes it's inadvertent, sometimes copied, a humorous parody, other times an homage, and still other instances being simply amazing coincidences. And sometimes obversely there is very little similarity than what we had imagined. I recall when I played one of the Scriabin preludes, a listener thought that it was derivative, i.e., the coda was deemed very similar to a coda by Albeniz. When I went to listen, it didn't sound very close, at least to me! So I think it can be in the eye--or the ear--of the observer/listener. Whenever I trip over one of these, and there is definitely a likeness, I'm always amused--without fail. Probably it's the same for you.
Thanks for listening and commenting. It's hard to play, but a very satisfying piece of music.
David