Why Google translate api may not fully translate a string?

Question

API

The resulting array should always contain 15 elements.
The & sign in the string stops the translation, I replaced it with a regular expression and.
I also sin on the combination etc.), but above it is clear that (Ill.) does not stop.

https://translate.googleapis.com/translate_a/single?client=gtx&sl=auto&tl=ru&dt=t&dj=1&source=icon&q=${categories_string}

I took cheat sheets here https://codepen.io/zefzero/pen/kkvqox
https://stackoverflow.com/questions/26714426/what-...