Auto chain executes when publishing version despite event handler filtering on 'Regular Document'

I have an event handler triggered on "Document created" for a specific doctype. The event handler has "Current Document is 'Regular Document'". After creating the document successfully (with event triggered and auto chain run ok), I publish the document using an auto chain (linked from an action button).

Expected result: when publishing, the auto chain would not execute, as I am not creating a regular document.

Actual result: the auto chain executes

Workaround: I can add the following 'Custom EL expression' = 'Document.isProxy() == false' to prevent the auto chain from being executed.