There is an uninitialized variable in USceneComponent which was added in 4.11 to control when the virtual function OnUpdateTransform is is called after the component was moved:
/** If true, OnUpdateTransform virtual will be called each time this component is moved. */
uint32 bWantsOnUpdateTransform:1;
This is not initialized and presents undefined behaviour. In our particular case, this was false, and prevented the OnUpdateTransform from ever being called, which broke behaviour on a derived type.
Proposed fix:
We have initialized this to true in the USceneComponent constructor.
The bWantsOnUpdateTransformvariable is working as intended. As you mentioned, the release notes state that it needs to be set so that issues such as this can be avoided.