Without knowing the context, I would tentatively agree that your example seems more like a mistranslation. Nevertheless, in my experience those tend to be the exception rather than the rule. I've seen a lot more cases of subtitles (both professional and fansubs) erring by being overly stiff and literal than the opposite.

> You really think "sus" will stand the test of time, be intelligible to viewers years and decades from now? It's at least a debatable point although you're comparing it to Japanese that by your own admission has survived a quarter century.

Well, "sus" has been on Urban Dictionary for about 20 years, and Wiktionary has a citation from 1972, so it's not like it's some radically new term that is likely to come and go in a short period of time. Besides, plenty of creative works use language that becomes dated over time, and that doesn't make them bad.