CiviMail links with to many clicks from only two people
Seems plausible, especially if you consider scenarios like two influential users who might have forwarded the email to a group of friends, but also through normal use (eg repeatedly clicking from an email while thinking about donating) or something else.

You could review logfiles to see whether the times and remote hosts of the clicks recorded suggest an issue in tracking, whether the visitors all came from the same origin IP, and whether the timing of the visits suggests any further information.