When a session times out because of inactivity, the workflow is automatically saved as draft. This is convenient for saving changes to workflows. However, it provides a false sense of security if there is a start form or any task forms in the workflow. Even though changes to the form are applied, if the workflow is not actively saved by the user, the form changes are lost.
Please auto-save form changes where the "Apply Changes" button has been clicked when the form times out and the workflow is auto-saved.