- In the Expanded format, there's already a rule that says you can't include Professor Sycamore and Professor Juniper in the same deck; players must choose one or the other. The same rule applies to Professor's Research, meaning it cannot be in the same deck as Professor Sycamore or Professor Juniper.
Source:
TPCi Announcement (2020-01-09), TPCi Rules Team (2020-01-09)