The signal going into the Ditto has the cab in it (or not if you turn it off), so you should expect that. What are you wishing it did?
so what happens is, Rig A is used to record a loop (amp and cab rig), then I switch to Rig B (amp and cab) but the Rig B cab is also effecting the sound of the Ditto in the effects loop. So its a cab after a amp and cab.