Steps to reproduce:
1) Navigate to monitoring->Hosts->Graphs. (Host - Zabbix server)
2) Reset the filter  **  
3) In the filters Hosts field add - Zabbix server (or any other Host that has graphs).
4) Apply filter
5) Press F12 and check console.

Result:
Console error - 500 (Internal Server Error).

Expected:
No console error.