This is relevant for the Timesheet module of the Classic UI.
When a resource's timesheet is opened, the aggregation / totals row shows a sum that is far above the actual sum of the individual rows.
One or more of the projects added to the timesheet have an issue with the PRWBSSEQUENCE.
Check the PRWBSSEQUENCE column of the PRTASKS table. When tasks are created using a supported method, such as:
this column is populated correctly.
If robots are used to create tasks using just the URL, from the browser, then there are chances that the same number is populated against all tasks in this column. This method is not supported.