Oh No !! The Wine Cellar Window ?!

We noticed there is a beam or mullion at the centre of the wine cellar window.
It should be a one piece glass window.
What happened?

We missed that out in the final drawings. 
One  #@$#%%*&;!! beep beep .. little line.

However, managed to get HH to fix it by removing the mullion and re-order full pane glass.

Mullion to be removed from  wine cellar window.