After December update, unable to open encrypted PDFs on mobile devices

Our vendor appliance (Totemo) is using an open-source library to create password protected/encrypted PDFs.

Those PDFs were readable until probably mid/end of December 2019.

The error is simply "The document cannot be opened because it is corrupted or damaged.

The same PDF can be opened without problems on a W10 workstation.

I have uploaded such a PDF, the password is "Nussbaum1!"

Environment: Android 10 December 2019 Patched
Adobe Acrobat reader version 19.9.2

Expected result: after entering the correct password, the encrypted PDF is shown

Observed result: after entering the correct password, the error "The document cannot be opened because it is corrupted or damaged" is shown.