Sometime over the past month or two, luci app statistics graphs broke for me.
Currently I'm running OpenWrt SNAPSHOT r12416-b9c1cf1657 (r7500v2) built with imagebuilder.
luci-app-statistics - git-20.061.71931-cf09705-1
The symptom(s) are graphs do not appear as usual. Instead I see broken links. The last known working version of luci-app-statistics for me was January time frame.
I've tried updating /etc/config/luci_statistics
I don't see anything obvious from logread, but upon /etc/init.d/luci_statistics restart, I did see
Thu Mar 5 07:08:43 2020 daemon.err collectd: configfile: stat (/etc/collectd/conf.d) failed: No such file or directory
and this directory and file are missing.