I’ve seen that with transsexual versus transgender - transsexual was the older term, but transgender is the newer term, but someone who’s perfectly fine with trans rights saying transsexual instead of transgender has a good chance of getting chewed out for the terrible bigotry of using the outdated term. I remember I was dating a trans guy back when I was first exposed to the concept, and a SJW type got angry at me for using ‘transsexual’ which I thought was the scientific term. There’s also big arguments about transgender vs transgendered, trans vs trans*, transgender vs trans-gender, and many more little variants that really shouldn’t be a big deal.
And note that it’s almost always PC-warrior types who make the distinction, I’ve never known an actual trans person who cares about it, generally they’re glad if you call them by the correct pronouns and don’t make a big deal out of it. (By ‘actual trans person’ I mean someone who actually identifies as a gender other than assigned at birth and tries to live their life that way as opposed to the ‘I self-identify as trans because I dress androgenously sometimes at university, I’m so modern’ types).