In the vault with Gratiana's soul jar:

Upon slipping a soul jar into your backpack (NOT Gratiana's), attempting to slip a different (INCLUDING Gratiana's) jar into your backpack will close the dialogue window and no action will be taken.

I did not try talking to Gratiana with the wrong jar.

Additionally:

After curing the burning pigs and sending Feder to the hideout...
Attempting to initiate dialogue with Feder using a character with Pet Pal opens and then immediately closes the dialogue window.

Last edited by Flailinggnome; 21/09/16 01:54 AM. Reason: New bug