Simple and straightforward; thanks.  I have only a very minor question:

— Section 3 —
      As such, SFFs, SFC-aware SFs, and SFC
      Proxies SHOULD discard any NSH packets with the O bit set and Next
      Protocol set to something that is not itself an OAM protocol.

What happens if they don’t discard them (what interoperability failure or other harm)?  Is there any reason to advise further?  Or does this not need a BCP 14 “SHOULD”?