Source: sentence above is translated
For example, a few days ago I asked it to write a professional followup email to remind someone about a deadline, and it used the sentence "I hope this email finds you well". This is common in English but in my native language (Spanish) most people wouldn't use a sentence like that in a professional email, so using machine translation would never generate it.
As an example, I reused that task from my real work. Here is the same email generated in two ways:
1. Prompt in Spanish + machine translation to English:
Dear candidate,
I am contacting you again as I wanted to remind you that the application period for the postdoctoral researcher offer with me is coming to an end. If you are still interested in applying, I would appreciate it if you would reply to this email as soon as possible.
I understand that you may be very busy, but I would like to remind you that this is a unique opportunity to join our research team and develop your career in this area. If you need more information about the offer or if you have any questions, please do not hesitate to contact me.
I hope I can count on your response soon.
Sincerely,
2. Prompt in English, no translation:
Dear [Candidate],
I hope this email finds you well. I wanted to remind you that the deadline for the postdoc position we discussed is quickly approaching. As we discussed, this is a fantastic opportunity to further your research and collaborate with our team.
I wanted to check in and see if you have any questions or if there is anything I can do to assist with your application. Please let me know if you need any additional information or if there is anything else I can do to help.
I look forward to hearing from you soon.
Best regards,
In my view (native speakers would be welcome to chime in and confirm/refute) while both could be OK and the first wouldn't make the candidate run away or anything, the second sounds more idiomatic in English. The first sounded perfectly natural in Spanish, but not that much when translated because the choice of sentences is not what most people would use in English.
Of course, option 2 is only better assuming enough knowledge of English to write the prompt. Otherwise, translation is the way to go.