Nope. Downloaded it, moved it to the ZIP 250 disk that I keep all my AHP files in, then uninstalled 3.310 and installed 3.311.
Then I'm not sure. If you uninstalled first, then you likely would have used the "Full" installer, not the "Update" installer. (I'm guessing the full one).
I just checked - the updater is 134KB (not 143), so perhaps that is part of what the installer "stub" needs to download to do the rest of the install?
Did you notice anything similar after any previous installations?
What is the date stamp on that file?
The only other thing I can think of is that when running an executable off the zip drive, Windows might cache it locally, in case the media is ejected during the install. I can't verify that, but is sounds reasonable.