Each date field needs a calculated value auto-entry option. To make sure dates do not change, click the "Do not replace existing value of field (if any)" option. Selecting the "Prohibit modification of value during data entry" option stops users from manually entering a date in browse mode (if that helps).
For the Concept date field, it would look like this:
If (valueListField = "Concept"; Get (CurrentDate); "")
Hope this helps!