I'm totally guessing here, but a pattern I see with bots/spammers is they'll sign up and post a few simple "decoy" messages, then come back later and start editing to include their spam links. Whatever algorithm caught and momentarily inconvenienced you, may have been designed in some way to counter certain spam bot tactics. Who knows.
I see people get really upset on FB because they have old posts that get dinged for "community standards" issues and they believe someone reported them. This is especially troublesome for people that have their account privacy settings to "friends only" because then it appears that one of their FRIENDS reported them.. when in reality, FB has "AI" bots that scour the entire site and find things they "think" are offensive, and automatically ding you for.
This is the world we live in! Getting more complex every day.
Richard