MACD on advanced chart works fine when interval of 1 day is selected, giving a Y axis range up to 50. When you select a smaller range such as 1 hr the Y axis range changes to 1000 and the lines obviously look flat at this scale. There does not seem to be any way to limit or adjust the Y axis scale to a sensible range.
You can make it work if you refresh the page so the change interval option code needs a refresh adding.