Hi. I'm using InDesign CC 2015.2 (220.127.116.11 x64 Build)
I'm combining this two features: "lined content" + "anchored object"
When I combine this two, text content of duplicated frames in never updated after that.
Try it your self:
This works fine. Text content of frame is updated.
BUT now try to place source TEXT FRAME to another text like a anchored object.
This never updates text content.
I also discovered more buggy behavior:
When you only change position of anchored source TEXT FRAME, your link ("Internal Linked Object") suddenly completely disappears from the list.
Please try I it your self somebody. Is it the same in your case too?
It's probably a pretty rare case because most people wouldn't think of using those two features together.
You can file a bug report here to make sure it gets seen by the engineers: