-PreviousSourceBuiltSdk legs are trying to download the SDK from an incorrect URL. I.e. for SB_CentOSStream10_Offline_PreviousSourceBuiltSdk_x64:
Downloading source-built SDK from https://builds.dotnet.microsoft.com/source-built-artifacts/sdks/dotnet-sdk--10.0.100-rc.1.25451.107-centos.10-x64.tar.gz...
Log - internal
Notice the extra - in filename: dotnet-sdk--10.0.100-rc.1.25451.107-centos.10-x64.tar.gz
Download from the correct URL is successful.
@mthalman @ellahathaway were there any recent changes in this branch that could have affected this?