It was a bit strange that nxos starts with a colon and that a cisco message didn't have a mnemonic. Cisco messages by my experience always contain a triplet and this one isn't, and doesn't seem to have a timestamp either. If you say that this was recorded the way you mentioned then i believe you :), they just looked a bit odd.

Do all messages from the same device look the same? Or these are just the exceptions?

Also what is nxos?