I'm not sure if this was reported. I couldn't find it if it was. If you change an svn check-in comment after the check-in while the change is pending in TeamCity, the comment does not change either while the change is still pending or after the build.
e.g. A change was checked in with "Comment A". The check-in comment was changed to "Comment B". When the change is pending in TeamCity "Comment A" displays. After the build that incorporates the change is run, the comment for the check-in still displays "Comment A".