I would like to point out that I have attempted to resolve the exact same issue with my Quickbook Online / Tsheets integration through the Tsheets support service, and they have been absolutely ineffective at fixing the issue.  I am beginning to think that the integration is total garbage and am not sure what I am paying for if I can't do something as simple as track time against projects in Tsheets, and have that synced appropriately to Quickbooks Online.