Importing many TXT files in a Portfolio (Mac)

Importing many TXT files in an AA9 PDF-Portfolio don’t work as expected.

Context : Some TXT files are stored in one parent-folder containing many sub-folders (about 3000 TXT files). They are exported from Apple-Mail (I’m trying to backup my mailboxes in a PDF-Portfolio...).

Importing them using Acrobat for Mac put hundreds files at the root level of the PDF-Portfolio, some sub-folders are empty, some files are at a wrong place : they all seems blowed.

Doing the same thing with the same files using Acrobat for Windows works as expected : no problemo.

Did someone already experienced that ?

See attachment (screenshots) here :

JR