It looks like you’re asking about the phrase — possibly a search term for a Vietnamese subtitled video or drama episode.
If you instead meant a (research paper, PDF, or document) related to “unexpected business” with Vietnamese subtitles or translation — that is unlikely, as “vietsub” typically refers to video subtitles, not academic papers. unexpected business 1 vietsub
If you’re referring to the popular Korean variety show — season 1 — then yes, that show has been widely fansubbed into Vietnamese. You can find "Unexpected Business season 1 vietsub" on various fan sites or video platforms like YouTube, Bilibili, or Vietnamese subbing communities (e.g., subteam, Kites, etc.). It looks like you’re asking about the phrase
However, I don’t have specific information about a video or series titled exactly with Vietnamese subtitles (vietsub). or Vietnamese subbing communities (e.g.