Reminder: all applicants are advised to obtain properly authenticated translations of any non-official language present in any of the documents to be gathered. See the instruction guide and information related to "Gather Documents."
This is standard across most of the immigration related applications. Documents containing non-official language text must be accompanied by properly authenticated translations.
Since applicants do not ordinarily present their full passport until the documents verification interview (typically done attendant test), and only submit a copy of the biographical pages with the application itself, many either overlook, forget, or deliberately ignore the instructions relative to non-official language in passport stamps.
Whether or not that is problematic at the interview depends. I deliberately did not get a translation for stamps dated prior to my landing as a PR, but the dates of those stamps were readily recognized as such, and the stamps were also readily understood in context with other stamps on the same page. Nonetheless, I did this knowing that technically the instructions required me to provide a properly authenticated translation, and the interviewer could have taken note that I had failed to follow the instructions.
In any event: all applicants are instructed to obtain properly authenticated translations of any entries in documents which are not in an official language.
In other words it is correct to say one was not asked, because actually all have been instructed. And again, this is standard, so there really should be no confusion about the obligation . . . even if, like me, some feel it will be easy to get away with not following this particular instruction.