"Could not find domain for" error message when loading or unloading plist using launchctl over ssh

I have a Launch Agent that checks the logged-in user's keychain for the existence of a user certificate.
On some devices, I can ssh into them as a local admin and manually load and unload the plist using launchctl. On other devices, attempting to do this returns the error: "Could not find domain for".
A Google search of the error found an explanation that this error appears because it's necessary to ssh to the device as the same user who is logged into the device. But I don't think this is accurate, because on some devices, I am able to load and unload the plist from an ssh connection different than the logged-in user. Has anyone seen this "Could not find domain for" error when attempting to load a plist using launchctl via ssh? Thanks.