@mirjam_465, oh dear oh dear, you started a sentence in written form with ‘And’. Repeat after me.
“One must not start a sentence in written form with the word and”. 
joking aside, English is a funny old language . (With both equal emphasis on funny and old) tricky homonyms are just one example of the English language being a bit bizarre.
I think it’s important for people to remember that when it comes to the English-language. There are different variants of it. The two most prominent being American English (EN-US) and great British English (EN-GB) . There are other variants of English, of course, but most the Commonwealth countries tend to be somewhat closer to EN-GB. While the difference between the two most prominent variants of English may not be immediately apparent in general day-to-day use. If you dive a little deeper. The difference between the two can be quite distinct, especially in terms of spelling and phrasing . I have elaborated a little bit on why this is in another topic which can be found here. Needless to say what is considered a mistake can often come down to which of the two most prominent variants of English one has a preference for.
You can probably guess from the phrasing I’m using. Where I’m from and which of the two most prominent variants of English I have a preference for 
The point is, with regard to the English-language and subtitling. Whatever you do, you are never going to make everybody happy. In the case of myself being British, I noticed many things that would be considered as mistakes in the English subtitling. Given that most of the shows on here are subtitled according to EN-US.
Too be honest the mistakes I notice don’t bother me all that much because I am aware that in most cases, the individuals doing the subtitling use English as a second or third language And I am aware that EN-US could be considered easier to learn than its British counterpart. I know the fact that the mistakes don’t really bother me, may surprise some, as we British are known for having something of a superiority complex when it comes to the English language. I can honestly say as someone else in this topic, mentioned. University grade English for subtitling of overseas programming is not expected and nor should it ever be, especially in case of Viki as the vast majority of subtitling is provided by volunteers who give up their spare time so we mustn’t be overly critical. I think in some of the other topics I’ve seen on here. People can be overly critical, which annoys me a bit.
On a personal note, I often think the subtitling on Viki is often better than the supposedly ‘professional’ subtitling that ■■■■■■■ provides for overseas programming.