Problem with nagios plugin

I have some problems with nagios plugin installed on librenms.
We use distribuited configuration with 1 nms core, 1 db server and 6 pollers server external without redis but only with memcached. Nagios plugin is installed only on core server not on pollers.
The control start with green tag on the line
57 years 9 months 1 week 19 hours 18 minutes 34 seconds
but after 10/15 minutes become blue and the control not check the service.
After few minutes the control became green and the check control is ok.
This is con

Can you help me?