The changes made in #1493 used a workaround for the Windows ARM Dockerfile:

It manually deletes the NuGetScratch folder instead of calling into NuGet to clear local resources as the AMD64 Dockerfile:

Calling the NuGet command was problematic because it was getting a failure attempting to remove the NuGetScratch folder. This particular problem could be resolved by setting USER ContainerAdministrator before the RUN command that installs PowerShell. But when that change is made, it leads to test failures in the VerifyAspNetImage_AppScenario and VerifyRuntimeImage_AppScenario tests because of #1054. There might be a way to resolve the testing issues through some magic combination of Dockerfile commands. It just needs to be experimented with.