Major - Any edit on UEFN while UEFN is syncing will cause a network error

Repro:

  1. Open live edit
  2. While you see the session loading, place a mutator down in UEFN
    UnrealEditorFortnite-Win64-Shipping_G93lvi11Zr

(I also duplicated a couple of other props too)
3) Network error on live edit.