This error indicates an error occurred while trying to transcode data across codepages. IEM currently supports deployments that are all running in the same codepage, so likely the endpoints that are failing are in a different codepage than the server. Look for any filenames in the action that might be codepage specific (special or accent characters), or if relevance substitution might evaluate to something that contains unique characters. Gathering a client diagnostics to review the logs should provide a bit more detail.
I’ve hit that too… Looked up codepages on good/bad machines and could not spot a difference.
In the end the BF client on the transcoding error PC was one rev back (9.2.5.x instead of 9.2.6), so I upgraded it. No problem since !