It's very unlikely to matter. While it's impossible to rule out somebody caring about this somewhere, I don't think this is something to worry about.

The primary concern with dates not matching up in your resume would be falsification of your work history. An inaccuracy of a few weeks in the end date is not plausible as a falsification, because what difference does it make?

I also would expect discrepancies like this to be fairly common, because many people will be going from memory when putting down their dates of employment, and may mis-remember.

For an internship, they may not even check.

It's very unlikely to matter. While it's impossible to rule out somebody caring about this somewhere, I don't think this is something to worry about.

The primary concern with dates not matching up in your resume would be falsification of your work history. An inaccuracy of a few weeks in the end date is not plausible as a falsification, because what difference does it make? Especially when we are talking about an internship that is a short-term position anyway.

I also would expect discrepancies like this to be fairly common, because many people will be going from memory when putting down their dates of employment, and may mis-remember.

For an internship, they may not even check.