Orange 30 not printing properly in center of Build Plate

I have been printing for a few weeks with my new orange 30 and it has been working awesome, but my last 3 prints the center section of the print successfully prints the raft on the build plate, then the supports start to fail- but toward the outer parts of the plate supports still print fine. On the last print (it was a section of hull for a large pirate ship) the center supports all failed but the print still printed. So I am not sure what is going on. I bought new FEP film for the VAT and I have been releveling the bed every print, so I know its not that.