Hi Emerson,
Sorry about the delay in the reply. I moved your comment here as it's more relevant to this open feature request and also maybe this other bulk actions request:
The behaviour you're experiencing here is the expected behaviour, as adding a new default populated field and republishing already existing documents could cause breaking changes to user's applications. I'm not sure it's so dangerous with a boolean, but the problem might be how republishing affects other fields in the documents. I'm reaching out to the team to get more information about this.
The workaround for the moment in your case to trigger a default boolean value for hundreds of pre-existing documents would be to use the import/export feature (beginning on the medium plan). You would export all the documents, run a script to update all the boolean fields and re-import them, this would trigger the publish again on all these documents and the content would stay the same except for the boolean field.
I realise this is less than ideal and I think this is why something like this is a good candidate for bulk actions. I'm also going to reach out to the UX research team about this to get their input.
If/when anything changes for this we'll update you here.
Thanks.