Hello, Billy.
I don't know of any changes in Monterey, Safari 16, or BookMacster 3 which would have directly caused this, but stuff like this happens sometime with iCloud, and upgrades are generally one of those times.
First of all, you did not mention where you had BookMacster installed. For the configuration you describe, you should install BookMacster to do syncing on only one Mac. Having BookMacster sync on more than one Mac in this configuration would create a
sync loop, which is probably the cause of the problem.
The issue you describe implies that iCloud has no records of Folder 1 or Folder 5. This is a typical type of iCloud corruption.
Quote:after cleaning the iCloud sync
Do you mean that you removed all items from iCloud and then exported from BookMacster as described
here? If not, this is the fix you should try, and is as far as I know the only fix for all problems of this type.
Quote:I did succeed to recover something correct on the mobile devices
Are you saying that the problem appears to be fixed?