Hi Tim,
just tested your bigger package on the latest 2.7 (dev version) and it works fine, regardless the filenames being quite long: as said in the PM the truncation could potentially happen when the package is imported into the SCORM activity i.e. the browser will play no role here, just Moodle, since the truncantion will probably remove the filename extension so the assigned MIME type will be document/unknown instead of text/html, forcing the browser to download that file instead of showing its HTML content.
I could be wrong but when I clicked on your link at the time of your first post the filename was not truncated instead it missed dots e.g. a_long_filename_with_no_dotshtml.
I'll try to find some spare time to test it on 2.6 and 2.5 (the latest being now supported) to exclude any issue in the last Moodle versions.
BTW, I'm happy you've found a working workaround for your 2.1 instance.
HTH,
Matteo