Underrated comment.

interesting. a quote from the oxford style guide mentioned (for BrE, of course):

• judgement (moral, academic etc)
• judgment (legal decision only)

the guide’s own wording also says “… moral judgement”. so according to oxford legal decisions can be called “judgments” but everything else should be called “judgements”?

Also using both metric AND imperial at the same time

it’s not just legal usage; in AmE it’s supposed to not have an e anywhere

And even aside from the "ton"/"tonne" difference, it used to be "tun":

https://www.etymonline.com/word/ton

ton(n.1)

[measure of weight or capacity], late 14c., "the quantity necessary to fill a tun or ask of wine;" the word is identical to tun (q.v.) "large barrel for wine, ale, or other liquid," often one of definite capacity.

The "weight-and-capacity" sense was (eventually) given its own spelling. The spelling with -o- became established 18c. (OED says "from c. 1688"); it is attested from 14c (tonne), and, though not phonetic, may have been retained partly because of the prevalence of Old French tonne, Medieval Latin tonna in legal forms and statutes in England.

They had to remove the u because Colour has OUR and it sounded too "communist"

/j

I believe that the general convention in both British and American English

though I'm sure that it's not consistently followed everywhere

is to use "the other guy's" spellings for proper nouns for things that were named on the other side of the Atlantic. Like, we in the US will normally refer to the British "Labour Party", even though that's not how we spell "labor".

goes looking for a British movie poster for Terminator 2

This says that it's a British poster, and it has no "e":

https://www.vintagemovieposters.co.uk/shop/terminator-2-judgement-day-movie-poster-5/

You likely want to choose an example where the term isn't part of a proper noun.

i thought it was just an AmE thing. apparently it’s also common in some british regions. outside of these regions (including the entire commonwealth) it’s “judgement” which is also what my phone keyboard gives me.