We are coming across a number of undocumented implicit code conversion triggerd in transmissions from CD SI to other CD nodes.
BinaryMode = YES
Sysopts = perm=600
This combination (existence of any sysopts) triggers a (hidden) additional sysopt of xlate=yes that causes an unwanted code conversion on the remote node.
This can be healed by adding binary and/or xlate=no to the sysopts.
Nothing of this is documented.