@Adriaan I tried again with your above images in East US with both GPT4o and GPT4o-mini and it worked just fine.
This seems like a transient issue and no issues are reported now in East US region.
You could also check this from your end from the Azure Portal --> Service Issues section: https://portal.azure.com/#view/Microsoft_Azure_Health/AzureHealthBrowseBlade/~/serviceIssues
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Please clear the browser cache and try again to check if that works.
If you encounter the same issue, again, please let me know. I would be happy to assist you further.
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