It has become very apparent, even in popular languages. Going to give y'all three examples here:

• Spanish for English speakers assumes you're learning North American Spanish, and marks a ton of things as mistakes as a result. On top of that, some of the things it teaches you are just not very correct in general. Yes, people will obviously understand you, but it's the same as Google Translate saying something without understanding the nuances of what is going on
• Russian for English speakers. This one was hilarious. I speak it at native level, and decided to do the placement test as a gag. I did not pass it. Half of the exercises were straight up garbage.
• Japanese for English speakers teaches you practically nothing. It's repetition and memorization of the same phrases, without any actual learning involved.

You are way better off using apps like Busuu. You get speaking practice, feedback from the system and other people, and it goes into an okay amount of detail for grammar and vocabulary, for the upcoming exercises. It's not perfect, but it's better. For Japanese specifically, just avoid these to begin with. It's not a good time. Download yourself Renshuu for writing practice, and a copy of Genki for everything else