I wouldn't say this is normal. That said, it need not raise a red flag or suggest that this would be a predatory conference or something you must stay away from. It doesn't inspire confidence, but it doesn't need to hurt confidence much either.
This sounds like a relatively minor issue and the kind of thing that is easy for the person setting up the conference website to miss in testing. Keep in mind that many prestigious conference have websites set up by academics volunteering to do so as part of service to their academic community, who are very busy, and for whom building robust websites is not their full time job.
There are predatory and sham conferences. If the conference is archival, check out Beall's List of potential, possible, or probable predatory scholarly open-access publishers and search around the web for information on the conference.
Email the organizers to tell them about the issue. You might even learn something about the credibility of the conference by who responds, and how.