Very odd and annoying bug to report on AO Ex. After nearly every render SU (only) becomes totally unresponsive while still using 100% CPU. I need to force quit SU or WindowServer to get out of it.
I am running AO Ex 2.01, MacOS 10.13.6, 2.9 GHz Intel Core i7, 16GB of RAM.
If it helps, I can also force quit WindowServer using Activity Monitor, which automatically logs me out, but keeps SU running. After login SU is responsive again.
Not certain when this started, but either was 2.00 or 2.01, definitely not the 1.xx version.
 Using SU 2018 Pro edition