Is there a name for that phenomena? It used to happen to me with reddit.
Especially disappointing for longstanding problems that I would walk away from and return to at a later date. I would of course initiate a renewed effort with a websearch containing key words. I guess in a sufficiently idiosyncratic/unique way that I would find my own thread, but not recognize it. Momentarily get excited like "this person has the precise same problem as I do!" hoping there would be a solution in the thread. Only to realize that the whole thing was a little too framiliar and it was myself, last year, struggling with the same problem having made zero progress.
Do you think that's why you found your own writing? Like if I am trying to research the present question and I do a search with keywords like fediverse repository knowledge lemmy kbin URL search reddit I could imagine finding this because it is an unusual combination of words. But if I were to use totally different phrasing I doubt I would get here.