> Hi, any update on this?

I was planning to submit a bug report, but hadn't because I don't have a reproduction recipe nor have I definitively pinned it down on Semantic.

Since I don't have a reproduction recipe, I haven't made much progress. I tried advising my after change hooks:

  (defadvice semantic-change-function (around my-advice-semantic-change-function activate)
    (let ((window-start-prior (window-start)))
      (my-msg "DEBUG: During semantic-change-function, window-start change:%s,%s" window-start-prior (window-start))))

Same defadvice for: c-after-change jit-lock-after-change. I also activated this advice for semantic-idle-core-handler. Basically this was to catch one of them in the act of scrolling the buffer. However, I encountered the bug with these in place and none showed a window-start discrepancy.

If you have a reliable reproduction recipe, that would be very helpful.