The last nightly builds was purely jQuery improvements. Beyond that no other code was touched. The few nightly builds before that were all "Install from Web". I find it hard to believe updating caused your issue, but rather something else is going on.
You're basically hitting REGEXP limits, but I've no idea how on a userlist. Please check the _comprofiler table and ensure you don't have any users with an avatar column that's extremely long. Best I can gather is if it's only affecting that field then somehow an extremely long string was stored to someones avatar column causing the preg_match for gallery images to fail, but it'd have to be thousands of characters to do that.