Interface Builder Build Failure in mixed Swift/Objective-C Project - ios

Question

I have a fairly complex situation that will be better with help.
This is an iOS app with mixed Swift and Objective - C.
Objective C classes subclass from Objective C classes only.
I have one Swift class named SettingsViewController.swift that extends from a Swift library class called QuickTableViewController. QuickTableViewController is a framework installed via Carthage. https://github.com/bcylin/QuickTableViewController.
After I set this up, I receive a build error when navigating to "Main.storyboard". I can still run the app, but I can't see my IBDesignables in the Interface Builder. The build error shows in the output detail (Figure 1), and shows "Failed" in the main status pane - with a warning icon (Figure 2).
Figure 1
Figure 2
The failure trace leads to the bridging header import line in my *.m Objective-C files :
#import "TestApp-Swift.h"
So.. I have an objective-c view controller (*.m) that creates the SettingsViewController.swift view, but it throws this error. I am not subclassing from swift, just using the bridging header in a view.m and a project that has a swift view that sub-classes a swift library class.
Here is how I create SettingsViewController for navigation in my .m file:
UIViewController *settingsVC = [self.storyboard instantiateViewControllerWithIdentifier:#"SettingsTableViewController"];
if (settingsVC) {
[self.navigationController pushViewController:(UIViewController*)settingsVC animated:true];
}
else {
NSLog(#"ERROR, Could not segue to Settings Table View.");
}
Any help will make me happy. The Interface Builder needs to happily show my IBDesignables and keep working if I use Swift libraries for views in this mixed project.