Privileged API user cannot edit SSH key

With both 3.3.4 and 4.0.0-rc1 a CO privileged API user cannot edit an existing SSH key.

Here is an example for 4.0.0-rc1:

curl \
--verbose \
-u 'co_2.rest_user_01:XXXXXXXX' \
-X PUT \
-H 'Content-Type: application/json' \
-d @ssh_key_edit.json \
'https://registry-dev.skoranda.scgvm.net/registry/ssh_key_authenticator/ssh_keys/1.json'

The file ssh_key_edit.json is

{
"RequestType":"SshKeys",
"Version":"1.0",
"SshKeys":
[
{
"Version":"1.0",
"Person":

{ "Type":"CO", "Id":"2" }

,
"Comment":"Uploaded via REST call",
"Type":"ssh-rsa",
"Skey":"AAAAB3NzaC1yc2EAAAABIwAAAQEAr9amUAycDrDj2f2kLkK6b5X5DYr+4kmRcYfjcOQG9capsUDh44E8C1KKKRtVZNCM4QAXjHHuIQhb7/YysH6XpjUypzHciDNyJ6f3H0Phrcu9X5HSXlPNuyHlq1rtxtuXnd/UPmrZlSuy1Kt4bjjk5EYI6XMXQjlZMet9mT8y0kB1NALGqfLm1LesjShEmKCqP97fj//jRakm661TDdphjKR7e/O6wB80BHZAUznd+4XqYoQ8wPMWFKk21ZtwNWEpgooPhwC956BmsGRXHzySct/LISNAwbQdNaxTKeWdLGvsD6uivBsbBe2egrkCB0UKzcyXTuQv3W4cElAzDFROEQ==",
"SshKeyAuthenticatorId":"1"
}
]
}

I have verified that the CO Person ID is 2 and that the existing SSH key has ID 1.

The server returns a 401.