Your daily quest activity resets at 5:00 AM your in-game time, and Guild activity resets at 2:00 AM UTC.
If your in-game time zone is different from UTC, all activity and titanite earned between 2:00 AM UTC and 5:00 AM of your in-game time zone will not be counted in today's Guild activity. It is counted towards the Guild activities of the previous day.
To avoid this, you should avoid collecting activity or titanite and upgrading Glyphs during this period.