Consider overhang AB...

The distributed load w creates a moment MB that acts clockwise on the right end of overhang AB. An equal magnitude moment acting in a counterclockwise direction is applied by the overhang to simply supported span BD.

Here is Canvas object wihch demonstrate the problem.
The expression for the deflection in the simply supported span at C produced by the counterclockwise moment MB is:

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Simply supported beam – concentrated moment at support