To replicate bug, I duplicated a composition which contains a layer that uses a master property controlled by a dropdown effect. Immediately upon copy and paste of the composition in the Project window, ALL master properties controlled by a dropdown effect across the entire project are reset to their default. In the history dropdown under the Edit menu, tons of actions are suddenly added that were not user initiated including dozens of "pull properties"

After Effects 17.1.3 (Build 41) on Windows 10 Pro