Description of problem:
We see on an OCP deployment ovn-controller taking 41% of the system's RAM:
[trozet@fedora process]$ cat ps_auxwwwm  | egrep 'USER|ovn-controller'
USER         PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
root        3824  0.0  0.0 143732  2324 ?        -    Apr19   0:11 /usr/libexec/crio/conmon -b /var/run/containers/storage/overlay-containers/6d11511d3356979d09e19079b3a52f7f1c58c8353945337f30aa80c21f37b03f/userdata -c 6d11511d3356979d09e19079b3a52f7f1c58c8353945337f30aa80c21f37b03f --exit-dir /var/run/crio/exits -l /var/log/pods/openshift-ovn-kubernetes_ovnkube-node-g8n2c_27d64f48-a34c-4cfb-acf2-1e6ac0c9605e/ovn-controller/0.log --log-level info -n k8s_ovn-controller_ovnkube-node-g8n2c_openshift-ovn-kubernetes_27d64f48-a34c-4cfb-acf2-1e6ac0c9605e_0 -P /var/run/containers/storage/overlay-containers/6d11511d3356979d09e19079b3a52f7f1c58c8353945337f30aa80c21f37b03f/userdata/conmon-pidfile -p /var/run/containers/storage/overlay-containers/6d11511d3356979d09e19079b3a52f7f1c58c8353945337f30aa80c21f37b03f/userdata/pidfile --persist-dir /var/lib/containers/storage/overlay-containers/6d11511d3356979d09e19079b3a52f7f1c58c8353945337f30aa80c21f37b03f/userdata -r /usr/bin/runc --runtime-arg --root=/run/runc --socket-dir-path /var/run/crio -u 6d11511d3356979d09e19079b3a52f7f1c58c8353945337f30aa80c21f37b03f -s
root        3983 28.3 40.9 6981276 6719588 ?     -    Apr19 2819:43 ovn-controller unix:/var/run/openvswitch/db.sock -vfile:off --no-chdir --pidfile=/var/run/ovn/ovn-controller.pid -p /ovn-cert/tls.key -c /ovn-cert/tls.crt -C /ovn-ca/ca-bundle.crt -vconsole:info


Additionally, there are complaints about OVN-controller:

021-04-26T08:40:59.094134419Z 2021-04-26T08:40:59Z|318134|ofctrl|INFO|OpenFlow error: OFPT_ERROR (xid=0x2320): OFPBRC_BAD_VERSION
2021-04-26T08:40:59.094134419Z ***decode error: OFPBRC_BAD_TYPE***
2021-04-26T08:40:59.094134419Z 00000000  ff ff 00 10 00 00 23 20-00 22 00 02 00 00 00 f1 |......# ."......|
2021-04-26T08:40:59.094164758Z 2021-04-26T08:40:59Z|318135|ofctrl|INFO|OpenFlow error: OFPT_ERROR (xid=0x2320): OFPBRC_BAD_VERSION
2021-04-26T08:40:59.094164758Z ***decode error: OFPBRC_BAD_TYPE***
2021-04-26T08:40:59.094164758Z 00000000  ff ff 00 10 00 00 23 20-00 22 00 02 00 00 00 f1 |......# ."......|
2021-04-26T08:40:59.094199271Z 2021-04-26T08:40:59Z|318136|ofctrl|INFO|OpenFlow error: OFPT_ERROR (xid=0x2320): OFPBRC_BAD_VERSION
2021-04-26T08:40:59.094199271Z ***decode error: OFPBRC_BAD_TYPE***
2021-04-26T08:40:59.094199271Z 00000000  ff ff 00 10 00 00 23 20-00 22 00 02 00 00 00 f1 |......# ."......|

This starts after OVS gets a bad OF packet and ends the connection:

2021-04-25T18:13:51.653255903Z 2021-04-25T18:13:51.643Z|57494|connmgr|INFO|br-int<->unix#979216: sending OFPBMC_BAD_LEN error reply to OFPT_FLOW_MOD message
2021-04-25T18:13:51.653255903Z 2021-04-25T18:13:51.643Z|57495|vconn_stream|ERR|received too-short ofp_header (0 bytes)
2021-04-25T18:13:51.653255903Z 2021-04-25T18:13:51.643Z|57496|rconn|WARN|br-int<->unix#979216: connection dropped (Protocol error)
2021-04-25T18:13:51.653255903Z 2021-04-25T18:13:51.643Z|57497|connmgr|INFO|br-int<->unix#979216: 4005 flow_mods in the last 17 s (344 adds, 3642 deletes, 19 modifications)
2021-04-25T18:13:53.003691314Z 2021-04-25T18:13:53.001Z|57498|ofp_msgs|WARN|unknown OpenFlow message (version 255, type 255)
2021-04-25T18:13:53.003691314Z 2021-04-25T18:13:53.001Z|57499|vconn|ERR|unix#1015512: received OpenFlow version 0xff != expected 06

Happening on multiple ovn-controllers in the cluster. Initially ovn-controller complains:
2021-04-25T18:13:51.871355080Z 2021-04-25T18:13:51Z|15499|ofctrl|WARN|req_cfg regressed from 1547 to 0
2021-04-25T18:13:52.763487507Z 2021-04-25T18:13:52Z|15500|rconn|INFO|unix:/var/run/openvswitch/br-int.mgmt: connecting...
2021-04-25T18:13:52.766052647Z 2021-04-25T18:13:52Z|15501|rconn|INFO|unix:/var/run/openvswitch/br-int.mgmt: connected
2021-04-25T18:13:53.002004331Z 2021-04-25T18:13:53Z|15502|ofp_msgs|WARN|unknown OpenFlow message (version 255, type 255)
2021-04-25T18:13:53.002112470Z 2021-04-25T18:13:53Z|15503|ofctrl|INFO|OpenFlow error: OFPT_ERROR (xid=0x2320): OFPBRC_BAD_VERSION
2021-04-25T18:13:53.002112470Z ***decode error: OFPBRC_BAD_TYPE***
2021-04-25T18:13:53.002112470Z 00000000  ff ff 00 10 00 00 23 20-00 22 00 02 00 00 00 11 |......# ."......|
2021-04-25T18:13:53.002164034Z 2021-04-25T18:13:53Z|15504|ofctrl|INFO|OpenFlow error: OFPT_ERROR (xid=0x2320): OFPBRC_BAD_VERSION
2021-04-25T18:13:53.002164034Z ***decode error: OFPBRC_BAD_TYPE***
2021-04-25T18:13:53.002164034Z 00000000  ff ff 00 10 00 00 23 20-00 22 00 02 00 00 00 14 |......# ."......|
2021-04-25T18:13:53.002220215Z 2021-04-25T18:13:53Z|15505|ofctrl|INFO|OpenFlow error: OFPT_ERROR (xid=0x2320): OFPBRC_BAD_VERSION
2021-04-25T18:13:53.002220215Z ***decode error: OFPBRC_BAD_TYPE***
2021-04-25T18:13:53.002220215Z 00000000  ff ff 00 10 00 00 23 20-00 22 00 02 00 00 00 14 |......# ."......|
2021-04-25T18:13:53.002778877Z 2021-04-25T18:13:53Z|15506|ofctrl|IN

Version-Release number of selected component (if applicable):
ovn2.13-20.12.0-24.el8fdp.x86_64

How reproducible:
need to see if I can reproduce this. Happens after upgrade from 4.7.3->4.7.6