Broadcast flow cannot be monitored on Netgate

[cisco0613]

Hello,
I installed net-snmp on my netgate 1541 and on a 2100 and I cannot retrieve the broadcast stream per interface.
On the net-snmp website: http://www.net-snmp.org/docs/mibs/ifMIBObjects.html
(3-ifInBroadcastPkts)
The corresponding OID is 1.3.6.1.2.1.31.1.1.3.X.
X = interface number

.1.3.6.1.2.1.31.1.1.1.3.1 = Counter32: 0
.1.3.6.1.2.1.31.1.1.1.3.2 = Counter32: 0
.1.3.6.1.2.1.31.1.1.1.3.3 = Counter32: 0
.1.3.6.1.2.1.31.1.1.1.3.4 = Counter32: 0
.1.3.6.1.2.1.31.1.1.1.3.5 = Counter32: 0
.1.3.6.1.2.1.31.1.1.1.3.6 = Counter32: 0
.1.3.6.1.2.1.31.1.1.1.3.7 = Counter32: 0
.1.3.6.1.2.1.31.1.1.1.3.8 = Counter32: 0
.1.3.6.1.2.1.31.1.1.1.3.9 = Counter32: 0
.1.3.6.1.2.1.31.1.1.1.3.10 = Counter32: 0
.1.3.6.1.2.1.31.1.1.1.3.11 = Counter32: 0
.1.3.6.1.2.1.31.1.1.1.3.12 = Counter32: 0
.1.3.6.1.2.1.31.1.1.1.3.13 = Counter32: 0
.1.3.6.1.2.1.31.1.1.1.3.14 = Counter32: 0
.1.3.6.1.2.1.31.1.1.1.3.15 = Counter32: 0
.1.3.6.1.2.1.31.1.1.1.3.16 = Counter32: 0
.1.3.6.1.2.1.31.1.1.1.3.17 = Counter32: 0
.1.3.6.1.2.1.31.1.1.1.3.18 = Counter32: 0
.1.3.6.1.2.1.31.1.1.1.3.19 = Counter32: 0
.1.3.6.1.2.1.31.1.1.1.3.20 = Counter32: 0
.1.3.6.1.2.1.31.1.1.1.3.21 = Counter32: 0
.1.3.6.1.2.1.31.1.1.1.3.22 = Counter32: 0

On each interface, when I run the snmpwalk command, the netgate returns the value 0. Why?
On the other hand, I manage to retrieve information on the multicast and unicast stream. It shows me the number of packets on each interface.

Have you ever encountered this problem? Is this a bug?
Thank you for your answers.

[cisco0613]

Hello @jimp
Do you have an idea of ​​the problem ?
Thanks in advance