When using SNMPWALK to JSON preprocessing step it breaks if we get an unexpected NULL anywhere before the OID's we're looking for:

.1.3.6.1.2.1.10.7.2.1.15.1 = NULL
.1.3.6.1.2.1.31.1.1.1.1.1 = STRING: wan1
.1.3.6.1.2.1.31.1.1.1.1.2 = STRING: wan2

I'm looking for OID .1.3.6.1.2.1.31.1.1.1.1 here, but error states that:

no data was found

At the same time, this works fine:

.1.3.6.1.2.1.10.7.2.1.15.1 = null
.1.3.6.1.2.1.31.1.1.1.1.1 = STRING: wan1
.1.3.6.1.2.1.31.1.1.1.1.2 = STRING: wan2

And also this works:

.1.3.6.1.2.1.10.7.2.1.15.1 = STRING: NULL
.1.3.6.1.2.1.31.1.1.1.1.1 = STRING: wan1
.1.3.6.1.2.1.31.1.1.1.1.2 = STRING: wan2

This can probably be considered incorrect output from the device, but still we should not break monitoring of anything else because of this.

Probably related to: ZBX-22026