reproduced on ovn-2021-21.12.0-103.el9:

+ ip netns exec public1 join_group -f 6 -g ff05::2 -i public1                                         
+ ovn-sbctl list igmp_group
_uuid               : c3dbbc82-3854-42b3-8ebd-a7f01af11952                                            
address             : "ff02::1:ff00:123"
chassis             : 1530bcf1-d1ac-47a8-a940-26b5043397a7                                            
datapath            : 57094c53-8110-4a44-b835-1d493df99ad6
ports               : [c8002318-c232-4cb0-a287-7acd2d66fa91]                                          

_uuid               : d5f29346-60b7-42e3-8bd8-255585d25cf2                                            
address             : "ff02::1:ff00:23"
chassis             : 1530bcf1-d1ac-47a8-a940-26b5043397a7                                            
datapath            : 57094c53-8110-4a44-b835-1d493df99ad6
ports               : [c8002318-c232-4cb0-a287-7acd2d66fa91]                                          

_uuid               : 041c84b3-4a5d-4a29-8d25-7372406563e7                                            
address             : "ff05::2"
chassis             : 1530bcf1-d1ac-47a8-a940-26b5043397a7                                            
datapath            : 57094c53-8110-4a44-b835-1d493df99ad6
ports               : [c8002318-c232-4cb0-a287-7acd2d66fa91]                                          
+ grep ff05
+ ovn-sbctl lflow-list
  table=24(ls_in_l2_lkup      ), priority=90   , match=(eth.mcast && ip6 && ip6.dst == ff05::2 ), action=(outport = "ff05::2"; output; )
[root@kvm-01-guest09 bz2170306]# rpm -qa | grep -E "openvswitch2.17|ovn-2021"
openvswitch2.17-2.17.0-92.el9fdp.x86_64
ovn-2021-21.12.0-103.el9fdp.x86_64
ovn-2021-central-21.12.0-103.el9fdp.x86_64
ovn-2021-host-21.12.0-103.el9fdp.x86_64

Verified on ovn-2021-21.12.0-134.el9:

+ ip netns exec public1 join_group -f 6 -g ff05::2 -i public1
+ ovn-sbctl list igmp_group
_uuid               : a02ec8fd-eee3-4810-9869-0f0fd5ebd650
address             : "ff05::2"
chassis             : 583ae974-143b-4f03-bb55-3671d5c5a044
datapath            : 7b4f08d9-957a-4c26-9a56-c2d557100f9b
ports               : [dfc27072-682b-4ea0-b2d3-84b70b47afdd]

_uuid               : 43340cc1-ddf9-4c34-b00d-651fafac3666
address             : "ff02::1:ff00:23"
chassis             : 583ae974-143b-4f03-bb55-3671d5c5a044
datapath            : 7b4f08d9-957a-4c26-9a56-c2d557100f9b
ports               : [dfc27072-682b-4ea0-b2d3-84b70b47afdd]

_uuid               : 786a421e-668e-4699-b59c-2fc21a61e299
address             : "ff02::1:ff00:123"
chassis             : 583ae974-143b-4f03-bb55-3671d5c5a044
datapath            : 7b4f08d9-957a-4c26-9a56-c2d557100f9b
ports               : [dfc27072-682b-4ea0-b2d3-84b70b47afdd]
+ grep ff05
+ ovn-sbctl lflow-list
[root@kvm-01-guest09 bz2170306]# rpm -qa | grep -E "openvswitch2.17|ovn-2021"
openvswitch2.17-2.17.0-92.el9fdp.x86_64
ovn-2021-21.12.0-134.el9fdp.x86_64
ovn-2021-central-21.12.0-134.el9fdp.x86_64
ovn-2021-host-21.12.0-134.el9fdp.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-2023:3990