Say my opponent has a Sudowoodo with the "Roadblock" Ability on his bench, but it's currently disabled due to my active Alolan Muk's "Power of Alchemy" Ability. If I have five Pokemon on my bench when Alolan Muk gets KO'd and "Roadblock" becomes enabled, do I have to discard one of my five benched Pokemon before promoting a new Active Pokemon or not?
When you remove your Active Pokemon after resolving all effects that caused it to be KO'd, you must replace it immediately before resolving any other new effects that take place.
Source: TPCi Rules Team (2018-12-06)