Why Does Umbraco Return 206 and Delay When Accessing /media?

Questions
1

We are experiencing an issue with Umbraco (13.8.1):
When accessing /media directly, there is a noticeable delay in receiving the image — even when the image is very small.

In Application Insights, we observe that a HEAD request followed by a GET PROPERTIES() call is made, and eventually a 206 Partial Content response is returned.

Our setup runs Umbraco on Kubernetes, and we use Azure Blob Storage for media storage.

Can someone help with this issue?

2

Just a quick check; is the media cache correctly configured?

3

Thanks for your response, and I believe so.
I have been through the documentation many times
Here is the Umbraco configuration:
“Umbraco”: {
“Storage”: {
“AzureBlob”: {
“Media”: {
“ConnectionString”: “Umbraco__Storage__AzureBlob__Media__ConnectionString”,
“ContainerName”: “Umbraco__Storage__AzureBlob__Media__ContainerName”
}
}
},
“WebRouting”: {
“UmbracoApplicationUrl”: “WebRouting__UmbracoApplicationUrl”
},
“CMS”: {
“Unattended”: {
“UpgradeUnattended”: true
},
“Global”: {
“MainDomLock”: “FileSystemMainDomLock”
},
“Content”: {
“MacroErrors”: “Throw”
},
“Hosting”: {
“Debug”: true,
“LocalTempStorageLocation”: “EnvironmentTemp”
},
“Examine”: {
“LuceneDirectoryFactory”: “SyncedTempFileSystemDirectoryFactory”
},
“RuntimeMinification”: {
“UseInMemoryCache”: true,
“CacheBuster”: “Timestamp”
}
}
}

And in program.cs:
builder.CreateUmbracoBuilder()
.AddBackOffice()
.AddWebsite()
.AddDeliveryApi()
.AddComposers()
.AddAzureBlobMediaFileSystem()
.AddAzureBlobImageSharpCache()
.AddUHeadless({…})
.Build()