Something changed in the build ordering so that LinkabilityChecker runs before the actual assemblies are built.
This seems like a longstanding problem that just wasn't noticed before, setting RequiresDelayedBuild enforces LinkabilityChecker builds after the shared framework.

LinkabilityChecker's delayed build depends on trimmable project outputs,
but Arcade's batch-based build system (not solution graph) provides no
ordering guarantee within the same BuildStep. All managed projects,
including BuildAfterTargetingPack, were in BuildStep='managed' and built
in parallel — a nondeterministic scheduling change in the new SDK caused
LinkabilityChecker to run before its dependencies were built (IL1032).

Move BuildAfterTargetingPack to BuildStep='post-managed' in Build.props
so Arcade's target batching guarantees all managed projects complete
before delayed builds (like LinkabilityChecker) start.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

[main] Source code updates from dotnet/runtime

Diff: https://github.com/dotnet/runtime/compare/ebb0dea8739963992b38dae9a60185da2802d8d0..be2631fa380635f4e357ccdd0d140e2a8069800b

From: dotnet/runtime@ebb0dea
To: dotnet/runtime@be2631f

[[ commit created by automation ]]

[main] Source code updates from dotnet/sdk

[main] Source code updates from dotnet/runtime

[main] Source code updates from dotnet/aspnetcore