I understand what you mean. The notification that a text has been translated from one language to another, and the fact that there may be confusion. But users can give feedback like “This term is not correct here”, and accordingly the author of the text can change it for the language in question. Yes, maybe jokes, sarcasm, dialects will have to be avoided. Rather it can be used for translating documentation similar to the one here in Discourse Meta. But for everything else it will be at the discretion of the owner of the given forum. In my forum, every post/discussion/topic is now in 4 different languages, unfortunately I have no users and therefore no feedback, but I doubt that I will ever remove the automatic translation unless the price for one token becomes around $5 
In my other forum, which is entirely in Bulgarian, I enabled automatic translation only for English, yes it looked good, but it didn’t sound good That’s why I personally believe that if there is going to be automatic translation, it is better to have it activated from the very beginning of the forum, so that everyone knows and there are no misunderstandings. However, one of the users here shared about his forum with over 100k discussions in it that there is no problem with the automatic translation. So I come to the conclusion that it depends on the owner and the users of the forum. If it is serious like Discourse Meta, OpenAI and the like, then the translation is not good at all if it is machine-generated and unverified (in terms of reputation). But if it’s a regular forum, like mine… new, young, it’s not a problem for me to make mistakes that someone will notice, scold me for, I’ll fix them and we’ll become friends 
In other words, point of view 
My answer was translated from Bulgarian to English using Google Translate. If there is a mistake, please forgive me. 