Why is "tomorrow" displayed as the "Date Modified"?
I get that all the time when I download a file from Europe when the time zone differences are not corrected. Dates can be set far in the past and far in the future with simple commands like touch and the finder just reports the metadata / date stored in the files in question.

No real mystery or worry unless you are in some way trusting a file’s date for processing or record keeping. In that case, you’ll need to audit for the correct times and catch things that show up with non-sensical dates or dates off from the current time by some deviation you set.