@Arne Koning Thanks for reaching out. I am able to reproduce this issue at my end will check with Product group team on this and will update you. Meanwhile as a workaround can use the REST Api https://learn.microsoft.com/en-us/rest/api/apimanagement/current-preview/apis/create-or-update?tabs=HTTP#apimanagementcreateodataapi
api-version=2023-03-01-preview allows import of odata type.
We apologize for the inconvenience caused by the issue. Feel free to add a comment if any questions.
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