It's two bugs, but since they're related to the same spell, i'm posting them here.
Bug 1: Prevent the summon warding from even working.
Steps to reproduce:
Cast -ward teleport
Then, try casting any of the following:
Banishment
Dismissal
Undeath's eternal foe
Expected result: You get summon warding
Actual result: You don't get summon warding at all
Bug 2: Make summon warding permanent on the area.
Steps to reproduce:
Cast any of the following:
Banishment
Dismissal
Undeath's eternal foe
THEN cast -ward teleport
Expected result: Teleport is warded off, and after the duration, summon warding fades
Actual result: Summon warding is now permanent. It does not fade.