I tested it with the free package of Jetpack and a CRED Edit Form, which should show the post after editing it.
This works just fine.
This must be a very specific issue.
At first, I will look into your site, but I cannot promise a fix.
Then, if I cannot fix it, we will require a Test Server (this is free of charge) and you can deploy your site on that Server, to which I will have full access.
We can then check if it's a server issue or not.
Also, could you please give me the exact Error that happens?
Thing is, "There was an error whilst submitting the form" is not a CRED error message.
It doesn't exist in the code base.