Caused by contributing gold to your guild shortly after Weekly Reset.
If you have contributed to your Guild Tasks shortly around Weekly Reset (7 AM GMT) your gold may not appear to have added to the your Contribution on the Guild Roster.
This is caused by the game client not refreshing immediately after the daily reset has happened. For example, if you were in the guild menu just before reset and then contributed after the reset happened, your client wouldn’t refresh so your contribution will be made to the previous week.
Fixing the problem
To prevent this issue from occurring, please completely close and reopen the game just after reset to force the game to sync with the server and update for the current week's Guild Wars. Weekly Reset happens at the same time each week, but it can take a little while longer for the changes to appear on all platforms are devices. If you still have an issue, contact support with 'Missing Rewards' as the Request Type.