I am encountering a strange issue with one of my forms. The form is embedded in a custom module using the HUBL syntax. When I redirect the form to a thank you page the form submits correctly and redirects, no problem.
As soon as I switch to using an inline thank you message the form no longer seems to work. There are no validation states applied so I assume that the form submits the data correctly, however the callback that shows the message is not running.
How can I figure out what is going wrong?