This is intended. As Blizzard clarified in a hotfix note this past Thursday, players should be able to complete both the initial quest for three dinar and weekly quest for a fourth. Most players missed out on doing this earlier in the week, as the quest was temporarily removed while developers worked to address a bug allowing the quest to be completed multiple times in a row, instead of just once per week.
Fixed an issue where “Turbo-Boost: Infinite Growth” could be completed more times than intended. It is intended that players can complete this quest once per week (including this week) after initially completing “Turbo-Boost: Trade Must Flow”. Players who completed this quest multiple times will find that it remains unavailable until others have caught up.
What has not yet been made clear is whether a proper catch-up is enabled from the start, so players who are concerned with acquiring dinar as soon as possible should probably try to complete this quest before the weekly reset, just in case.
Ideally, the catch-up will be enabled and players who do not acquire all four dinar this week should simply be able to complete the quest twice next week instead. We will endeavor to confirm this shortly after tomorrow’s weekly reset.