According to a couple reports, the volume bug fix update for the European Samsung Galaxy Nexus is going out OTA already. Supposedly, it started late yesterday, and a few people have received the update, which measures in at 1MB. This is a week ahead of what Google/Samsung indicated, although it makes sense that they might slowly roll it out piece-meal to test it out.
This new patch only updates the phone's build from ITL41D to ITL41F, while keeping the version of Android at 4.0.1. If you are one of the folks that have experienced this bug, go to Settings > About phone > System update to see if you have it. Then, let us know in the forum if you have it and if it seems to fix the issue.