OK I think I’m getting closer to the cause. I have 2 text form fields on the page and 1 button. Both forms are set to having the data source field value as default value. If I update BOTH, I can submit the form. If I update one I get “Invalid form”. If I update the other, it’s fine! It seems similar to this issue: Issue when updating a row with app builder form. Yet a little different. Running v 1.24.2