I'm on version 3.4.13

Update of an item that is on a template that is attached to a large number of hosts, no error, but the update doesn't happen, and the screen goes back to items.php 

not seeing any errors in the apache logs on the front end or the zabbix-server log

Steps to reproduce:

1. update of an item that is on a template that is attached to a large number of hosts at least 500.  
2. items.php?form=update&hostid=60&itemid=1021584
3. modify the field, hit save
4. ... you are then left on a screen items.php that is empty

Result:
See screenshot...
See log file...
See memory dump...
Expected:
See screenshot....
See attached patch file...