Don't panic. This is a feature, and one we are quite proud of.
And the simple solution -- to cut to the chase -- is to always schedule showings for prospects from the ShowMojo Dashboard.
What's Really Going On
When a prospect schedules a showing, ShowMojo remembers the prospect's browser. When the prospect goes to schedule another showing, ShowMojo conveniently fills out all their information for them. This is a common activity, as ShowMojo specifically cross-markets your similar listings (and only your listings) with each prospect.
If you schedule a showing for a prospect from a schedule-a-showing page, ShowMojo will treat you as a prospect and remember your details the next time you go to schedule a showing.
Additionally, ShowMojo logs this activity as being completed by the prospect. That's not a big deal, though it can throw off some of your reporting.
As noted above, ShowMojo recommends that you always schedule showings from the ShowMojo Dashboard.
One Additional Thing to Check
In some extremely rare cases we have seen customers confuse showing links with scheduling links.
Showing links start with "showmojo.com/s/" or "showmojo.com/m/s/". (By comparison, normal listing links start with "showmojo.com/l/" or "showmojo.com/m/l/".)
Showing links are specific to the showing. ShowMojo will never offer you a showing link to distribute for advertising. And, in general, it is very difficult to get the two mixed up. But if you are ever in doubt, check the link for the "/s/" characters. As long as you don't see them, everything should be fine.