AMP Caches make transformations to AMP documents for serving which renders the AMP documents invalid AMP. This is expected / normal.

If a user loads a document on the AMP Cache and appends #development=1, the validator will run and display some errors, which is a source of confusion for developers in some cases.

This feature request is to add some special case javascript code to not run validation when appending #development=1 to an AMP document present on the AMP Cache. Instead, a simple message could be displayed suggesting that the user do the same on the original non-cached document.