Everything works fine, until you change from channel A to Filter channel B. Almost in all input signal range, the output filter signal is dramatically distored like an overload in the middle of scale. Here are some pictures. First pic. - Ch. B, second one - Ch. A. Yellow - Input, Blue - Output.
In the same time corresponding 8 and 24 bit examples works fine on both channels.
Modified project in attach. To choose between Flter Channels comment/uncomment #define FiltA at the beginning of main.c.