How to autopopulate a field based on a user's role using an object trigger?

We have created an object trigger.

Object: Activity

Trigger: After Create

Script:

def Field=Field

def secCtx = adf.context.getSecurityContext()

if (secCtx.isUserInRole('Role1')||('Role2')||('Role3')){Field = 'YES';

}

else if (secCtx.isUserInRole('Role4')||('Role5')){Field = 'NO';

}

It was working for Roles 1-5. However, it is also auto-populating as 'YES' for other roles (Role6, Role7, etc.) which should not happen. This field should only be null/blank/no value for other roles.

What would be the possible reason for this?