Exactly. Now if you'll excuse me I've got to go tell James R. Kirk about that smiling Vulcanian over there so he can inform... Space Command? UESPA? The Star Service? I'm so terrible with remembering names... I hope that isn't one of the two different 'only death penalty left in the Federation' offenses...
MUST...TRY...CAN'T...RESIST...
"James R. Kirk" is probably
the single best example of a deliberately contradictory retcon, yes. Also "lithium crystals" and "hand lasers," both changed because of concerns about the implications of using real-world subtances/tech with known properties to do fantastical sci-fi magic and stuff.
"Vulcanian" isn't a contradiction any more than "Terran"/"Earther"/"Earth(wo)man" are with respect to humans, and was likewise used in at least two episodes
alongside "Vulcan"—namely "This Side Of Paradise" and "Errand Of Mercy" (TOS).
"Space Command" and "UESPA" aren't contradictions and haven't really been overtly retconned, AFAIK. They both pop up in specific contexts in episodes where "Starfleet" is
also used. So they are meant to be distinct in
some way, even if we can't discern all the particulars. The latter even goes on to be referenced in VGR and ENT! (And that's even without counting illegible dedication plaques full of in-jokes...in-jokes like the ones I
do realize you're making here, I swear! You can even test me with a psycho-tricorder to be sure!

)
"General Order Seven/Four" is certainly a blatant contradiction, but it was a simple error, not an intentional retcon. (Just an interesting bit of trivia here, I know this discussion covers
both types of situation.) What happened was that the regulation in "The Menagerie" (TOS) was actually
scripted as "General Order Four" and was only changed to "General Order Seven" very late, possibly even during shooting. Thus, when they referred back to that script for continuity purposes in writing "Turnabout Intruder" (TOS), they
thought they were being consistent. As Herb Solow would
put it:
"I understand that you science fiction people with your technical jargon have a word to describe this happening. It is known as a 'mistake.'"
OH, THE ANALITY!
...and THE WOMEN!
-
MMoM
[P.S.--I'm sorry I wasn't able to stop myself there, but it was just too hard. As hard as cast rodinium...or diamond...or tritanium...or whatever the hardest known substance
actually is.]