Business Rule "Set Field Value" with "When changing a value" recognizes always a change

In our 16.2.100, this rule recognizes a field change, whenever a field was set, e.g. via REST API, even when the field value has not changed.

When e.g. "red" is written to the field "Colour", and "Colour" was already "red", a change is recognized.

Also "Condition" with "Colour is modified" does not help.

Interestingly, in History, no change is noted of the colour example above. So Octane "knows", what has really changed.

We are looking for a solution, by which we mark Requirement Documents, which have changed after a synchronisation from another tool. The synchronizer writes always all fields of a requirement, independly if a field was changed or not.