Field Groups (fieldsets) not rendered

Field groups (fieldsets) configured on the form for a File node are not being rendered when that form is an inline entity form on the "parent" form.

This issue deals with the interaction between two modules, so, of course, I realize the problem could be with either module - but I'm posting it here first because field groups are working everywhere else in the site (used extensively), just not when a form is rendered by inline entity form.

I updated IEF from version 1.0-rc15 to 3.0.0-rc15 to see if that would fix it, but it made no difference.