Poll disappears when running cron

I am unable to use this module, and very sad because it would be very useful to me.
Indeed, the poll disappears from the node each time the cron is launched...
In order to make it appear again, I have to edit the node (for exemple, change one letter in the node). Then I save the changes and the poll is back.

But when the cron is launched again, the poll disapper one more time.
Can you help me?

Thanks in advance!