Calls to GET https://api.powerbi.com/v1.0/myorg/reports quit work correctly until last month. In the past, calls to this API returned the reports that a user had access to. The direct shared reports, the reports the user had access because of group membership on actual report, the workspaces the user had at least view rights on or was in a group that at least had view rights and the the user's own reports,.
Now the API returns only the reports that are direct shared and owned and not even all of those but a subset, it seems only from workspaces newly created, reports from the older upgraded workspaces are not coming showing. Access of the reports can be easily proven by using the "Shared with me" of app.powerbi.com or pasting a link to the report.