Mobile and PBI report migration

Hi I migrated SSRS from one server (ver. Jan2021) to another (ver. Jan2022). All was fine with rs.exe and migration script. I have only issues with PowerBI (.pbix) and Mobile Reports (.rsmobile) because only .rdl are migrated.
I got this error for every PBI or mobile report:

first phase: retrieve catalog
Folder: /Main/Area/Customer/Customer Editings/contents
(this is OK)

Second step: migration
Migrating Folder: /Main/Area/Customer/Customer Editings/contents ... FAILURE:
System.Web.Services.Protocols.SoapException: The item '/Main/Area/Customer/Customer Editings' cannot be found. ---> Microsoft.ReportingServices.Diagnostics.Utilities.ItemNotFoundException: Th
e item '/Main/Area/Customer/Customer Editings' cannot be found.
at Microsoft.ReportingServices.Library.ReportingService2010Impl.CreateFolder(String Folder, String Parent, Property[] Properties, CatalogItem& ItemInfo)
at Microsoft.ReportingServices.WebServer.ReportingService2010.CreateFolder(String Folder, String Parent, Property[] Properties, CatalogItem& ItemInfo)

it seems that parent folder (really isn't a folder but the PBIX report) isn't retrieved from Catalog.
any idea?
many thanks

Start with the rs.exe migration script and its catalog retrieval and migration steps, then trace the ReportingService2010.CreateFolder call shown in the error. Compare how .rdl items are handled with .pbix and .rsmobile items; done means the migration completes for those report types without the missing-parent-folder error.