@michall3
I carried out a test on my end and can you follow the below steps?
1) Select the form and expand the Title Field.
2) Select the Control Type to "Edit text".

3) Now, you should see the Update property. Make sure that it is DataCardValue8.Text
4) Try to save the details again.
Hope this Helps!
If this reply has answered your question or solved your issue, please mark this question as answered. Answered questions helps users in the future who may have the same issue or question quickly find a resolution via search. If you liked my response, please consider giving it a thumbs up. THANKS!