Revisions are sometimes missed

[mboynes]

Sometimes when previewing changes, neither wp_creating_autosave nor wp_before_creating_autosave fires, and thus the meta isn't saved to the revision. I believe it has something to do with timing; possibly that revisions aren't stored until WP has sent its first 'autosave' heartbeat. I haven't dug into the WP code yet to determine why that is. See demo below:

(Note, this is with #40 merged, so that meta previews work)

[adamsilverstein]

Right @mboynes the meta is only saved when the autosave fires. Possibly we can improve the logic of how this happens - any chance you can retest this in Gutenberg to see if its still an Issue?