I have found bug (unless if it was intended and I've missed its documentation) with the update property of DataCards. I have an app which has an edit form that updates a list within SharePoint. One of the fields within the form (a LookUp column to a document library) has a blank update property which upon the form being submitted would lead to this field of the record remaining the same (aka no update was applied). This is until sometime after 4/10/2023 (version 3.23034.13) at which point the functionality of the update property changed and would remove any previously existing data in the LookUp column when the form was submitted.
My first observation of this issue occurred 4/17/2023 and the last time a record was updated with out this issue was 4/10/2023 (no records on this list were updated between these dates). I'm assuming that means the issues was caused with version 3.23034.13 and beyond, since my app's version as of 4/10/2023 was 3.23033.15 and 4/11/2023 it was 3.23034.13 and stayed as this version until 4/27/2023.
As of 4/27/2023 the app is now running 3.23042.12 and I am still able to replicate this bug. I have also been able to replicate this using other field type such as date fields and text fields although I have not typed every field type.
There is an easy work around for this issue, which is setting the update property to either the DataCard control's main data providing property (ex: DataCardValue1.Text, DataCardValue1.SelectedItems, etc.) or ThisItem.FieldName and set the DataCard/Control's display mode to view if the field is something that shouldn't be updated by the end user but you still want the field's data displayed.
Hopefully this helps anyone encountering this issue and/or Microsoft employees to identify that this change has occurred.
