Why are all Iranian contracts set to end in December?

I submitted a load of Iranian transfers citing Persianfootball as a source for proof. When adding the changes, the default end date was set to December. This makes no sense to me because the Iranian season ended on the 13th May last season (about the same time as most European seasons) So this would mean that all contracts are set to expire midway through the season.

Is there any reasoning for this, or is this actually how it is in real life?

Here is proof of when the season ended btw https://en.wikipedia.org/wiki/2015%E2%80%9316_Persian_Gulf_Pro_League