System addons that explicitly set FormNames can result in loading the addon multiple times
If a system addon is created but FormNames are also entered, the addon will be loaded for both the system script environment and for each form script environment that is specified. An example where this causes errors is when registering system event handlers which can only be registered to a single addon.
Forms are not relevent in Library, System, or Server addons.
Adminsspires (Product Owner, Atlas Systems, Inc.) shared this idea