Wfm api 400 on schedule group import via cli

is it possible to import a schedule group with empty shifts via the wfm api without hitting a 400 bad request?

using genesys cloud cli v2.1.0 in au-1 byoc.
resource: genesyscloud_wfm_schedule_group

the error says “invalid shift data” but the json matches the schema. manual import works fine. looking for a workaround or known bug.