Using recrypt with PDF-1.7 - any known limitation?

[awied]

I'm running constantly in an error when trying to recrypt documents encoded with PDF 1.7 ("Unable to recrypt files, check that input and output files are clear and arguments are coool"). All other PDF documents in v1.6 or below are handled correctly without any issues.

Is there a known limitation (or issue) with PDF-1.7 and recrypt?

UPDATE:
The target (recrypted) file is being created but only partially. It seems the process stops somewhere in between. Here's the output of the log file:
[ 10/09/2019 12:06:35 ] PDFDocumentHandler::CopyInDirectObject, object not found. 383>

Thanks -Alex