Back-to-zero detection on counters

[troffasky]

How is this handled? It does not seem to be an issue with SNMP counters when a firewall has rebooted, for example.
Zabbix 7.0 monitoring Unifi switches with Unifi Network API.
I am having a problem with traffic counters that are probably going back to zero when "something" occurs on the switch, perhaps a loss of connectivity with the controller.

"tx_bytes": 2671104751379,
"rx_bytes": 490292731426,
"bytes": 3161397482805,

This results in silly spikes of traffic in the graphs:

Item configuration:



Yeah, I can do an "in range" pre-proc step, but the threshold is un-knowable. I have gone all the way down to 4Gbps and still get spurious spikes anywhere from 500Mbps up.
Unfortunately I have not been able to find any documentation for the API, their KB article says it is found in a location that does not exist.

[troffasky]

I duplicated the item without the change-per-second step and can see this is the real issue:

I am guessing this is an issue with the API returning 0 randomly. So I will add my range check step before the simple-change and that should eliminate the spurious spikes.