stay_open and list-type tags

[Anton Kovalenko]

Is there a way to set a list-type tags while in stay_open mode?
When trying to use "-sep ," I get "Ignored superfluous tag name or invalid option: -sep ,".
Example:

-sep ,
-xmp-dc:subject=tag 1,tag2
test.png
-execute
Ignored superfluous tag name or invalid option: -sep ,
    1 image files updated
{ready}
-j
-xmp-dc:subject
test.png
-execute
[{
  "SourceFile": "test.png",
  "XMP:Subject": "tag 1,tag 2"
}]
{ready}

If "-sep ," is in inirial arguments, it looks like it's ignored

[StarGeek]

Try putting -sep and , on separate lines.