Hey Julie,
You can allow this behavior in the Schedule of the Smart Campaign, but you cannot control how many times. For example, you can allow them to fill out the form once/ day, or once/week, but there isn't a way to stop them after filling the form out twice despite the time in between. I saw a similar conversation awhile back about workarounds, but cannot remember what the result of that conversation was unfortunately.
Can you give a little more info about the glitch? Sometimes Marketo just does weird stuff.