tested with script in https://bugzilla.redhat.com/show_bug.cgi?id=2170305#c3

reproduced on ovn-2021-21.12.0-103.el8:

+ ip netns exec public1 join_group -f 6 -g ff05::2 -i public1
+ ovn-sbctl list igmp_group
_uuid               : 6c2699c8-9fc7-4ab6-9699-2959b7237e08
address             : "ff05::2"
chassis             : 5984de3b-2b38-4958-a75b-9bbe79685718
datapath            : f174d88c-75aa-4d22-a626-a144a0f2f1dd
ports               : [f8bcc585-64b0-4a3d-9126-426b8a9e7905]

_uuid               : b44c3695-51a0-4934-a09d-f3abacab38bb
address             : "ff02::1:ff00:123"
chassis             : 5984de3b-2b38-4958-a75b-9bbe79685718
datapath            : f174d88c-75aa-4d22-a626-a144a0f2f1dd
ports               : [f8bcc585-64b0-4a3d-9126-426b8a9e7905]

_uuid               : af1aa1ff-74a1-4916-b918-5f42c77f449c
address             : "ff02::1:ff00:23"
chassis             : 5984de3b-2b38-4958-a75b-9bbe79685718
datapath            : f174d88c-75aa-4d22-a626-a144a0f2f1dd
ports               : [f8bcc585-64b0-4a3d-9126-426b8a9e7905]
+ ovn-sbctl lflow-list
+ grep ff05
  table=24(ls_in_l2_lkup      ), priority=90   , match=(eth.mcast && ip6 && ip6.dst == ff05::2 ), action=(outport = "ff05::2"; output; )
[root@kvm-01-guest06 bz2170306]# rpm -qa | grep -E "openvswitch2.17|ovn-2021"
openvswitch2.17-2.17.0-105.el8fdp.x86_64
ovn-2021-21.12.0-103.el8fdp.x86_64
ovn-2021-host-21.12.0-103.el8fdp.x86_64
ovn-2021-central-21.12.0-103.el8fdp.x86_64

Verified on ovn-2021-21.12.0-134.el8:

+ ip netns exec public1 join_group -f 6 -g ff05::2 -i public1
+ ovn-sbctl list igmp_group
_uuid               : 410ef255-dcb2-4b20-ad12-775150d67230
address             : "ff02::1:ff00:123"
chassis             : 957fbab7-d240-4598-8cce-73c9c2f4b9ac
datapath            : 44dd9b98-00c0-4a97-9b59-e0e04deced1a
ports               : [5c97e976-79b6-41ca-bcf5-478112bd58d1]

_uuid               : 5c53153e-ee73-474d-b83c-e5127797be25
address             : "ff05::2"
chassis             : 957fbab7-d240-4598-8cce-73c9c2f4b9ac
datapath            : 44dd9b98-00c0-4a97-9b59-e0e04deced1a
ports               : [5c97e976-79b6-41ca-bcf5-478112bd58d1]

_uuid               : f6a62bcf-fe09-47e1-8ab0-8ff29fee354b
address             : "ff02::1:ff00:23"
chassis             : 957fbab7-d240-4598-8cce-73c9c2f4b9ac
datapath            : 44dd9b98-00c0-4a97-9b59-e0e04deced1a
ports               : [5c97e976-79b6-41ca-bcf5-478112bd58d1]
+ ovn-sbctl lflow-list
+ grep ff05
[root@kvm-01-guest06 bz2170306]# rpm -qa | grep -E "openvswitch2.17|ovn-2021"
openvswitch2.17-2.17.0-105.el8fdp.x86_64
ovn-2021-21.12.0-134.el8fdp.x86_64
ovn-2021-central-21.12.0-134.el8fdp.x86_64
ovn-2021-host-21.12.0-134.el8fdp.x86_64

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (ovn-2021 bug fix and enhancement update), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2023:3995