Some items have bookmark property Zoom Level set to mixed values throughout the document. Disconcerting.
I recently tried the EverMap AutoBookmark plugin to Adobe to allow all bookmarks in a document to be set to Inherit Zoom.
This does the job but has an unwelcome side-effect: When viewing document using Evince bookmarks have off-by-one error.
As far as I can tell they appear as intended using Adobe products, and xpdf.