Background check - advice needed

Landed an offer at a top group and have a question about the background check process because I'm somewhat worried about it. I put a couple of unpaid internships on my resume which I wasn't given an official title for or the official title was just "intern", so I put down a title which reflected the work better (which may have been slightly exaggerated but more or less true) for example I was interning at a startup doing mostly marketing work so I put down marketing and growth intern. Another time was at a v small consulting firm, some of which would be strategy work so I put down strategy consulting intern.

I'm now worried that these job titles will get flagged in the background check process since they aren't official even though they describe the role more accurately. The bank has sent me a form to fill in all employment history which includes listing the job title, so was wondering if I should revert back to the original "official" titles of just "intern" on the employment form, or would that be an issue as it then wouldn't match up with my resume?

I also have another offer from an MM which I didn't use these job titles on my resume for, so I'd like to know if I am screwed as I would just take that offer instead. Many thanks for any insight.