Reverts to Follow's icon styles after saving block configuration

This is related to my comment on a similar issue: #1563508-5: Great if we could change our own icons. →

I have a theme that implements hook_follow_icon_styles_alter() to override the Small icon style with a new icon-path, so that it uses icons from my theme directory. After saving the block configuration, though, they are reverted back to the small icons that come with the Follow module.

The reason for this, as in that other issue, is that when the block configuration form is saved, the admin theme is active. The icon-path that's set in my theme's hook_follow_icon_styles_alter() is unknown because that template.php isn't included while saving the form. As such, the generated follow.css uses the default icon-path for the small icons. After saving the form, I have to delete sites/default/files/css/follow.css and refresh the page, so that follow.css will be saved using the icon-path specific in my theme.

I hope that all makes sense. I understand the problem but don't have any ideas for a solution—at least, none that aren't ugly hacks.