I've been having some problems with snort restarting on my Shield when downloading files. It didn't always happen, and I couldn't figure out why it was only happening when it did.
For example, some file downloads from the kids' Xbox would fail. I discovered that snort was bouncing up and down - taking down web access for everyone in the house - as they were attempting to update a game (or whatever needed updating). I also had problems downloading some smaller files (~8MB) from legitimate sites.
In any case, after applying all of the changes you suggested (except for the last one which doesn't seem to cause trouble for me), the shield seems to be behaving a lot better!
I echo this, since applying the updates I never need to reboot the shield and my internet rarely goes down. It just nice and stable, big thanks to all who contribute to this forum, thanks to you all we can continue to use this little box for the foreseable future.