When YouTube began building automatic transcriptions for captions, it regularly flagged any noise or music -- typically industrial noise -- with "[foreign]"
If it couldn't understand it, it was "foreign" for the longest time.
Haha, yes, it's fair when English subtitles write something like [speaks Japanese], especially when at least one of the characters is not supposed to understand what's being said (when they do, it's more appropriate to write "[in Japanese]: let's go shopping!").
Netflix sometimes takes the cake with what I consider the most outrageous option: writing "[in English]" when they mean "in whatever language the protagonist considers native", which is mind-bogglingly wrong and hilarious at the same time.
They do this with the English subtitles of the German production "Die Kaiserin" ("The Empress"): whenever Sisi is speaking in another language, say French, the subtitles will say "[in French] I love you...", and when she switches back to German they will say "[in English] I love you...". WTF, Netflix? Note this is unrelated to understanding German; it's mostly Netflix looking down on its customers and assuming they cannot comprehend there are people in the world for whom their native tongue is different to the viewer's native tongue.
This has happened in more shows, enough to know it's not a fluke, though Netflix is inconsistent about it.
Can confirm as well, although to my recollection it just shows up as if it's a word the transcription model heard, not "[foreign]" in brackets like with "[Music]" or "[Applause]". It's especially weird to me because I recall the auto-transcriptions being reasonably serviceable when they first rolled them out, only to degrade over time to the point where it was hallucinating the word "foreign" and dropping letters from words or using weird abbreviations (like "koby" for "kilobyte", "TBTE" for "terabyte", or, most memorably weirdly, transcribing the phrase "nanosecond-by-nanosecond" as "nond by nanc") if it didn't decide it heard another one entirely.
I also noticed a couple of months ago that YouTube seems to have quietly rolled out a new auto-transcription model that can make reasonable guesses at where capitalization, punctuation, and sentence boundaries should go. It seems to have degraded even more rapidly than the old one, falling victim to the same kinds of transcription errors. Although the new one has a different hallucination in silence and noise that it wasn't able to classify (which, incidentally, its ability to recognize things like music and applause seems worse than the old one's): where the old model would have hallucinated the word "foreign", the new one thinks it's hearing the word "heat", often repeated ("Heat. Heat.").
If it couldn't understand it, it was "foreign" for the longest time.