> 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)))
      ad-do-it
      (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.