Display/edit Sprout Form entry in front end
Sprout Forms improved support of this scenario in v3.0.0-beta.27. You can now use the setEntry variable to populate the Form Entry Model that you want to use in the Form Templates that you output using the displayForm tag. See the docs on Editing Entries for more info.

Populate a Front-End form with existing data

{# Get an instance of the your Form #}
{% set form = craft.sproutForms.getForm('application') %}

{# Get an instance of the Entry you'll be allowing a user to edit #}
{% set entry = craft.sproutForms.getEntryById(123) %}

{# Set the `entry` variable so your Form Templates know how to populate the fields with existing values #}
{% do craft.sproutForms.setEntry(form, entry) %}

{# Output your form as usual #}
{{ craft.sproutForms.displayForm('application') }}




Original Answer

I've looked into this and am considering this a bug. I've opened an issue on Github and will update my answer here when we have a fix in place.