Ball behind defenders

A high press and a much lower defensive line is going to need a different shape. You can see it on the screen visually with how you've set your team up there's a huge gulf in between defenders and midfield. We'd need pkm's from games to check what is happening, to me it looks like that formation needs a holding midfielder, but I'd probably swing by the tactics section and ask there as well because some of the better tacticians among the community would likely be able to help.