Why does the user get a response that an event is expired when cloning a form?

Today I had several registration links that were not allowing users to register.  They said they were getting messages that the event had expired or was closed.  The forms had been cloned from previous events.  When I opened the preferences section on the form, there was no expiration set and the form was enabled.  I didn't change anything, but when I closed it and the user tried again it suddenly worked.  This happened on the Mardi Gras Lunch, the State of the School Community Conversation and Dean Love's Talk Time with Students.  Unfortunately, all the links started working again before I could take screen shots.  I was using Firefox at the time.  Thank you for your help.

Thank you for contacting us.

It is probably that there was a temporary glitch with the expiration date option, although I do not see similar reports from other users. We will keep monitoring the service to see if anything is wrong.

If you notice the issue once again, please update this support forum thread.

Thank you.  We will.