Trigger Prototype Editing not working. - Host "x" does not exist or you have no access to this host.

Hello, 

I have noticed problem with editing trigger prototype. 

There is error visible: 

Incorrect trigger prototype expression. Host "Template_Dell_Compellent_ZBX_248" does not exist or you have no access to this host.

For Example I have used Compellent Template.

The problem looks that Zabbix is unable to recognize Template Name as Host user in Trigger Prototype Expression.

All changes are performed with account with Super Administrator Permissions.

Steps to reproduce:

1.  I want to change name of the trigger ( simple change , just name, but other changes also does not work)
2. Go to Template/ Discovery Rules / Select "Trigger Prototypes" 
3. Try to edit any of Trigger Prototype.
4. After Clicking Update Error is visible. 

I have also tried to export template, make changes in XML, and import, - the same result. 

Result:
See screenshot...

Expected:
Possibility to Edit trigger prototypes without errors.