EDIT - It’s working. All data was going into live dataset, not sandbox.
I am having this issue as well on heatherwood
Data input through preview loads to database fine. When it’s submitted from live site, it says successfully submitted but never shows up in database.
I did have database permissions set to members only, since this is in a members section. I tried changing to anyone to see if that fixed it, and it hasn’t.
Any other suggestions?