Server lag glitch in t7 hordes cross-platform

I have a full party, we tried to run t7 hordes twice and the server lag glitched. As we were playing all of us three console and one pc cross platformed, all experienced server lag. It got to the point where we failed a t7 due to server lag around wave 1-3 in both t7’s. We switched to t6 to see if hordes are glitched but the t6’s are running just fine. Did someone dupe again?? What’s wrong with t7’s?