A type built from the wrong source is no longer allowed to run

Installing a package brings a prebuilt version of its types with it, which is what makes installs and restarts fast. Recently the platform learned to check those prebuilt versions: the package now records which source it was built from, and the portal compares that against the source it actually holds. When the two disagree, the build is marked as rejected.

Marking it was only half the job. A rejected build could still be started — its pages activated, its background rules armed, its handlers registered — and code that was built from older source running against current data is exactly how a customer lost four documents' contents earlier this year. Stale code sitting unused harms nobody; stale code that is running is the incident.

So now it is not started. When a type's build has been proven to come from different source, the platform declines to bring up anything that runs it. Pages of that type show a short explanation instead — that a build exists, that the platform refused to run it, and that this is not a mistake in your code — and any request sent to it comes back with a clear "refused", never a silent hang or a misleading "still compiling". The Recompile button on that page is the fix: it rebuilds the type from the source this portal actually has, and every affected page comes back on its own once it succeeds. Where a deployment only accepts prebuilt packages and cannot rebuild locally, the message says that too, and names what has to happen instead.

Two things deliberately did not change, because getting them wrong would be worse than the problem:

• Packages published before this check existed still work exactly as before. They carry no record of their source, so nothing can be proven about them either way — and "we don't know" is not the same as "we know it's wrong". Only a build that states its source and disagrees is refused.
• The type's own pages keep working — its overview, its data model, its build diagnostics. Those are what you need in order to understand and fix the problem, so they stay available.