I have this same issue when generating update status reports. The report is not even updating the last check in fields correctly. I have tried recreating report, cleared cache and old tasks, restarted WSUS server, multiple syncs. We are running. Solarwinds Patch Manager 18.104.22.1687 on server 2008 R2.
Report might be broken due to different Data Sources used for its generation.
The best way to generate reports is to use one data source for one report where possible, mixing data sources may be painful.
We had pretty similar case recently.
Error in report was that data source for "Update Approval State" and "Update Approval Action" had used different DataSource then rest of fields.
I recommend as fix use the same Data Source for All fields in report: the best fit for provided report is change DataSource for all fields in generated report
"Computer Update Status with Details" --> "Computer Update Status With Approval Information".