It appears that the PDF document in [bug 1292316](https://bugzilla.mozilla.org/show_bug.cgi?id=1292316) now renders "correctly"[1] when compared to e.g. Adobe Reader and PDFium. Most likely this bug was fixed by a *somewhat* recent patch, or patches, to the `XRef.indexObjects` method.
Before just closing [bug 1292316](https://bugzilla.mozilla.org/show_bug.cgi?id=1292316) as WFM, I figured that it probably can't hurt to add it as a new test-case to avoid accidentally regressing this document in the future.
---
[1] Given that the XRef table is corrupt, and that we're forced to recover, there's generally speaking probably some question as to what actually constitutes "correct" in this case.