Hi there Guy Hummel
Thanks for using QandA platform
this might be becoz Azure ML Studio still supports v1 deployments for legacy workflows, but its testing features have evolved to prioritize v2 managed online endpoints. v1 deployments are functional and can be tested using CLI, SDK, or REST APIs, they are incompatible with the in-Studio testing feature, which focuses on v2 API. Try, either migrating your deployment to a v2 endpoint for full Studio compatibility or continue testing v1 deployments externally using CLI or SDK.
If this helps kindly accept the answer thanks much.