This can go both ways whether you understand both the original dub and the subtitle language that differs from the dub, for example: I recall watching a TV show episode where a conversation about a friend of theirs being drafted to war, but this piece of dialog was horribly translated: “He’s still a kid” as in the guy is his early 20s.
The subtitles in 日本語 however, used the worst wording for this idiomatic prasing by translating “kid” as in a literal minor (子供) when the real context is more on referring to someone who’s 20 years old or above (basically equivallent to saying “young man” / 若い人) which butchered the scene since the subtitles failed to express that.
I mean, do you know examples of a movie or TV show where the subtitles suck at translating the spoken dialog when it involves idioms, puns or even cultural references? Whether it’s French Dub & English Sub or vice versa (like English Dub > Spanish Sub & etc.) since each language has their own way of conveying a message.
Most of time cross culture is the issue which is your issue here, while rarely you will see subtitles mishaps which is because many shows nowadays offer offical subs or atleast have fan subs compare to old days when they were symbols like box or time adjustments issues not saying today perfect though as it still have the issue you have above unless you know culture of that medium you are watching