I have an encounter called: "COS: K56. Cauldron" and it when I delete it nothing happens. When opened it infinitely loads with "Untitled Encounter" and the save date becomes "Last save was on December 31, 1969 at 6:00 PM". I just want it deleted from my account.

I have something similar.  I have 2 encounters that I can't delete.  

I just gained another one just a moment ago.

Bump

I have the same issue, two old encounters from a finished campaign won't let me delete them. Not a huge issue, just a bit annoying. 

To delete a campaign it:

• Must be named
• Must be attached to an active campaign
• That campaign must not have any incomplete characters associated with it.

Try changing the associated campaign and saving it and then try to delete it again.

I have mine named but not linked to a campaign.  When I edit one of mine, it acts like a new one and is unnamed so I can't do what you suggest to delete it.

Good luck - I've had 2 encounters I can't delete for over a year.