The application and effect of end offsets are shown below in Figure 1. As seen in these images of a two-span continuous beam, moment does not transfer through the region of end offset.
Figure 1 - End offset demonstration
Redo this example using frame structure (two columns fixed at their base and one beam, with the columns being much more stiffer than the beam) rather than beam structure. Frame structure is a more relevant model for end offsets.