frameDidChangeNotification not firing under Sonoma

I have this code in my app:

	NotificationCenter.default.addObserver(self, selector: #selector(innerFrameDidChange), name: NSView.frameDidChangeNotification, object: mInnerTextView!)

mInnerTextView is not nil

I have this on initialization

	mInnerTextView!.postsFrameChangedNotifications = true

(and, yes, ! is bad, I know, this code has not changed in years)

The issue is that under Sonoma this notification is not firing nearly as often as in previous OSes. Specifically it does not fire when the window is resized, which does change the frame of mInnerTextView.

Anyone have any recommendations?

Thanks

Howard