Poll Answers Not Recording on Attendance Report

I'm a co-organizer for all of our webinars.  We recently switched to the webcast format to allow for more attendees.  Since then, it seems that we have issues with attendees' (at least 100 per presentation) poll answers registering and showing as answered on the attendance report.  When I follow-up with them regarding the issue, they all respond that they received a poll/answer submitted prompt after answering.  Of course, they don't think to take any screenshots of that during the webinar, so I don't have any attachments to upload.

Has this been a recent issue?  Is it because we switched formats from webinars to webcasts? 

Any guidance you can provide will be greatly appreciated.

Thanks!