PDF ingest via Bulkrax often fails to create thumbnail

Objects with PDF service files often fail to create a thumbnail. Sometimes it looks like the ingest gets stuck at file characterization leaving the fileset characterized as an octet stream, but there are also many instances where the files are correctly characterized as some flavor of PDF and fail to create a thumbnail.

Ingesting these same files via manual creation within Comet does trigger thumbnail creation so it appears to be an issue within the Bulkrax pipeline only.

Example item ingested via bulkrax: https://lib-comet-sandbox.ucsd.edu/concern/generic_object_ucsds/384743?locale=en

Same item created manually through Comet interface: https://lib-comet-sandbox.ucsd.edu/concern/generic_object_ucsds/384773?locale=en

Sample collection ingest that failed to create thumbnails: https://lib-comet-sandbox.ucsd.edu/collections/345240?locale=en

Importer: https://lib-comet-sandbox.ucsd.edu/importers/179?locale=en