Just a wild guess what its doing here:
its remembering which check boxes were selected, but on returning to the Main Portal page, the report records have a different sort order so the wrong reports are selected.
No, it should remember the ones you selected on the main portal. Selecting the ODBC source(s) you want to modify on the Change Data Source tool page should have no impact on the reports you originally selected on the main portal.
How did you return to the main portal? Did you click on the browser’s back button or did you click on the Return to Main Portal link at the top of the tools of the side navigation menu?
We were unable to reproduce the issue. However several updates to the main portal page were made and perhaps the issue is now resolved? Please logout, clear your cache, and log back in to try again. Please let us know if this resolved the issue for you and if yes, mark the response as an accepted solution.