10v10 kicking is on dedicated server (no rubberbanding tho), and while your game run smooth as butter at start, and troughout entire games on 4v4 in 10v10 in phase C the accumulated number of individual models in game is to much to handle for your CPU. Game is not optimised for such numbers and your fps drops even tho you dont realise it. Then server kicks you aafter you do a lot of looking around zooming in and out in same time when there is bazzilion units in game spawned by 20 players. That is really a lot for CPU to handle, especially if only one core gets all the beating. We are talking about surviving units from phase A, phase B and the additional reinforcements of phase C multiplied by 20.
I was also sure its not my PC issue (not top-end but also not old - overclcoked i5 with water cooling that reaches over 4.3GHz with 4 cores and gtx 970), untill i analysed carefully the replay and CPU load during it. And in phase C even replay starts to gradually slow down. Its playable but indeed slower. So yes, CPU struggle with it in phase C.
Indeed, it seems to be a CPU problem. While my GPU even at the highest setting is dangling its balls around out of boredom, my CPU can barely keep up as soon as I start zooming in and out, and that is on the lowest possible settings (with the exception of resolution and render scale).
I could understand that, if I were to come along with a dual core in a notebook, with all the thermal throttling and TDP limitations going on, but I am not. Yes, my CPU is not the newest, but I don't think I am unreasonable to expect that the 10v10 mode runs as advertised on a CPU that is four years old, even if that may be on the lowest settings.
P.S.: That CPU load happened only during intense, random zooming during a 10v10 replay, whenever I stayed at a single magnification level, the load would drop to about 80 to 90%. Not ideal, but not enough to expect a kick from the server.