UPD: The issue happens for text and comment questions. radiogroup, dropdown, checkboxes and other questions do not have this issues, since they do not update their values on blur.
To avoid this issue for text and comment questions, "textUpdateMode" property can be set to "onTyping".
If you have the following JSON, then on changing company name, focus goes to "Complete" button instead of "vat" question.
UPD: The issue happens for text and comment questions. radiogroup, dropdown, checkboxes and other questions do not have this issues, since they do not update their values on blur. To avoid this issue for text and comment questions, "textUpdateMode" property can be set to "onTyping".