Related Action Visibility issue

We have an Attach Files related action on a record with the following visibility settings: 

isusermemberofgroup(user(loggedinuser(),"username"), cons!CTM_GROUP_ADMIN),
isusermemberofgroup(user(loggedinuser(),"username"), cons!CTM_GROUP_STUDY_MONITOR),
isusermemberofgroup(user(loggedinuser(),"username"), cons!CTM_GROUP_UPPER_MANAGER)

When logged in as myself, an Admin, I am able to see and use the Attach Files related action, but when logged in as a Study Monitor or Upper Manager, the Attach Files related action is not visible at all. 

The original Visibility was set to: 

and(
if(rule!CTM_isMonitoringEventClosed(rf!eventID), false, true),
or(
isusermemberofgroup(user(loggedinuser(),"username"), cons!CTM_GROUP_ADMIN),
isusermemberofgroup(user(loggedinuser(),"username"), cons!CTM_GROUP_STUDY_MONITOR)
)
)

I wanted to remove the validation to allow the related action to be executed at any time by users in the Admin, Study Monitor, or Upper Manager groups. Am I missing something else that needs to be changed in order to allow this? The Process Model has a start form, which I read in other discussions may cause issues, but that doesn't explain why I am able to execute the related action as an Admin and not the user types. Permissions on both the process model and the record type are open to each of these user groups. 

Thanks for suggestions.