During TA: Changing angel in the team screen the change doesn't apply. It still shows the angel that was being used previously and it still uses that angel during the battle. Only after leaving the room does the angel change.
During CS: I changed my aegis to see that the current aegis being used is the one I changed from. (Libra to Sagittarius)
During CS: I changed my aegis to see that the current aegis being used is the one I changed from. (Libra to Sagittarius)