Ntopng takes down web configurator

[nwenos]

SG2220 & SG2440
pfsense version 2.3.2_1
ntopng version 0.8.6

The last 3 pfsense installs I've done I have run into issues were my web configurator page is inaccessible after about a day.  I can reboot the router and get back in for about a day and then I lose connection again.  I found if I remove ntopng package, then restart php-fpm and webConfigurator I can get back in.

I see messages like this in the system log, I'm not sure if they are related

[Lua.cpp:4617] WARNING: Script failure [/usr/local/share/ntopng/scripts/callbacks/second.lua][/usr/local/share/ntopng/scripts/lua/modules/graph_utils.lua:863: /var/db/ntopng/1/rrd/bytes.rrd: illegal attempt to update using time 1453671953 when last update time is 1485555109 (minimum one second step)]