(I don't have the powerpoint testcase, though I've heard talk of a PowerPoint testcase that runs afoul of this & martin may know more. I've just been working off of the attachments here.)
Bug 1544413 Comment 16 Edit History
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(I don't have the powerpoint testcase, though I've heard talk of a PowerPoint testcase that runs afoul of this & martin may know more. I've just been working off of the attachments here -- Florian's "Sample file" and violet's "reduced-testcase.html")