Another migration topic (LR5 > LR6 > LrD)

I am trying to migrate from Lightroom 5 (via a Lightroom 6 trial) to the cloud based Lightroom. When doing so, I get a confirmation that the migration was succesful, but unfortunatly, none of the photos show up in the library.

I tried multiple times (by recreating the libraries through ligtroom 5 and then 6), unfortunatly without a result (every time). I work on a Windows-PC.

Anyone experienced the same/has a solution?

A copy of the log file below, attached a printscreen of the confirmation in Lightroom and the resulting library.

  
  *******************************
  MIGRATION SUMMARY
  *******************************
  
  STATUS : [ COMPLETED with NOTIFICATIONS ]
  
  Source Catalog  : *****\2022_V5-2.lrcat
  Assets from Catalog  : 2496
  Assets Migrated to Lightroom : 0
  
  Number of Collections Migrated : Migrate-able( 1 ) After Migration( 3 )
  
  Number of Stacks Migrated  : 0 of 0
  Number of Stack Assets Migrated  : 0 of 0
  Number of Virtual Copies Migrated  : 0 of 0
  Number of Assets with Metadata Migrated  : 2496 of 2496
  Number of User Keyword Migrated  : 0 of 0 
  Number of Person Keyword Migrated  : 0
  
  *******************************
  NOTIFICATIONS
  *******************************
  
  Warning Messages
  -------------------------------
  * assetImportError
  * Develop settings were missing for some photos




  Develop setting not migrated for 2496 Asset(s)
  ********************************************************************************
  1->getDevSettingsExpected object of class AgMetadata at index 1, got value of type table. : 33 : *****\DSC00022.ARW 
  2->getDevSettingsExpected object of class AgMetadata at index 1, got value of type table. : 48 : *****\DSC00023.ARW