Heyo,
Sorry to be the bearer of bad news, but this is unfortunately still the case..
Uppercase words sometimes don't translate and sometimes mess up the translation. I am not entirely sure if this is an issue with the training data or the engine pipeline itself, but I believe it is the former. Nothing I can do about it at the moment :/
However, I will still disable this for DeepL. I could add this as an option too I suppose, but there's value in not letting the user change settings that (unknowingly) will affect translations. A tooltip would help, but from my experience, a lot of people don't bother reading.