unicode validation and/or presentation error

[rjsparks]

Somehow we have a set of minutes that cannot be inspected at /meeting/interim-2021-lpwan-02/materials/minutes-interim-2021-lpwan-02-202101191600-00.md but can at /doc/minutes-interim-2021-lpwan-02-202101191600/00/

We should find what codepath let us get into that state.

Interestingly https://datatracker.ietf.org/meeting/interim-2021-lpwan-02/materials/minutes-interim-2021-lpwan-02-202101191600-02.md (and I assume -01) do not crash, so Pascal probably saw and worked around the issue during submission.