Steps to reproduce:

1. I have a Cisco 615 device, and when I upgraded from version 6.2.8 to 6.4, I imported the official Nexus 9000 template from GitHub and associated it with two devices. The template import was successful.

Next, I tried to import the Cisco IOS SNMP template, which is associated with 615 devices. However, I failed to import it after trying five times. I suspect that this may be a system bug due to the large number of devices using the template.

As a workaround, I replaced the Cisco IOS SNMP template on all 615 devices with another template and shutdown devices in zabbix , which resulted in the Cisco IOS SNMP template being associated with 0 devices. I successfully imported the Cisco IOS SNMP template 

all template from officail github 

Result:
successfully imported the Cisco IOS SNMP template after change 615 devices template to another 
..
Expected:
import template when large number devices use