3793750 - KUT Default Value Rule Cannot Be Assigned to Field

In Adaptation Mode, for a given field the user cannot see the 'Rule' hyperlink of 'Set Default Value'. In other environments user may see this available and wonder why the difference 

SAP Sales/Service Cloud V1

1. Click in the profile menu
2. Select Adaptation Mode
3. As example, go to the Customers work center.
4. Click in the Accounts view.
5. Click in the + icon.
6. In the Quick Create pop-up opened, right-click the 'distribution channel' field.
7. User does not see the 'Rule' hyperlink of the 'Set Default Value' section in the right corner of screen.

Certain fields have application logic tied to them. For the example above, if you fill the 'sales organization' field and repeat steps 6 and 7 you will see the 'Rule' hyperlink of the 'Set Default Value' section in the right corner of screen.
For other environments, the application requirement logic may be fulfilled in the past, default value rule was then created and then later the application requirement logic was not fulfilled anymore (but default value rule assigned will still be tied to field).

Consider the possible application dependency the field may have with other fields in the screen.

There is another scenario where the "Rule" link to set a default value is available in Adaptation Mode, even not filling the "Sales Organization" field, which is the field controlling the dependency on "Distribution Channel", there is one possible reason.
In this scenario, some rule was added in the past to "Distribution Channel" field when the field was editable and the "Rule" link was available on adaptation mode.
 
Then after the rule already exists on "Distribution Channel" field, the Read-Only property was set on "Sales Organization" field later, keeping "Sales Organization" and "Distribution Channel" greyed out and not editable. 
The default rule link would be visible only if the field is on editable mode.

However, as the rule was added before the read-only action, the "Rule" link is visible on Adaptation Mode.
The reason for this behavior is that the Default rule will always overwrite any other logic in the filed as PDI, Code List Restriction and application logic.

SAP What's new page with feature delivery
SAP Help page with usage of feature 

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SAP Cloud for Customer add-ins all versions ; SAP Cloud for Customer core applications 2605