This is fairly complicated to repro:
1. create pages A, B, and C in the same space.
2. make B the child of A, C a sibling of A.
3. put in A:

4. put in B:

5. go to A and verify to that it shows the correct thing ("B – Here is an excert that contains a link to C.")
5. Now... change the name of "C" to "D".
6. Go back to A. You'll see that B's excerpt is gone! It should be there!
7. Go to B. Click Edit, then Save. (Don't change anything.)
8. Go back to A. Voila, B's excerpt is back!

I use

quite a bit, so this problem really bogs me down.