We should clear all fields or values.
We should clear the form, so to have it ready for new Posts.
That means it is correct that Fields that have originally no default value or so, are empty on a Form.
And that will be empty after an AJAX Submit.
What is not correct, is that some data from any other post, even current post, is mistakenly used to populate Fields that, on a "new post" form, should be empty (even after AJAX Submit).
I have investigated and updated the DEV in regard.
I see the issue you mention. You use the Post ID shortcode, that loads the current page ID, and after the AJAX action, the ID is the ID of the created post instead of the Current Post.
And that should mean, we do not properly clean the form (reset) it after AJAX.
You could use Custom Code, a CRED API filter, that allows the usage of a "container_id".
https://toolset.com/documentation/programmer-reference/cred-api/#cred_save_data
This allows you to get the ID of the Post where the CRED is inserted to.
Then, with the filter you can update the data of the created post, as example, it's parent post ID Field.
The more appropriate method would also be, to populate the Parent Post Picker in the CRED Form with the Post ID ShortCode in the value attribute, but it's also not working now, due to the same issue as you encounter in the generic Field.
But that, after we fix the issue, should be the recommended way to go.