Steps to reproduce:

1. Create a master template with an item and a trigger.
   

1. Create a linked/child template that is linked to the master template
2. Change the severity of the trigger in the linked/child template (override it)
   
3. Update any field (the description for example) of the trigger in the master template

Result:

The overridden severity of the linked/child template is now gone. Back to the same value as the master template trigger.

Expected:

That the severity of the linked/child trigger stays the same.