The preview seen in the input preview pane of the amplifer settings window does not sample at the speed set in the Chart View. It displays data from the chosen input according to a static algorithm using a polling min/max sampling mode, where min/max pairs are displayed at roughly 40 Hz. Baseline noise artifacts that occur at higher frequencies will not be displayed in the preview pane, but will appear in in the Chart view if its sampling speed is set high enough. This discrepancy usually is not evident until the sampling speed in the Chart View is set at or above 4000 samples per second, and is most apparent when applying the Mains filter.
Note: For an example of this behaviour, please see the video file located HERE.