In many big-budget movies one see octagonal bokeh balls, in TV talk shows even pentagonal ones are common! Because these movie budgets are not small and the cameras in general are very expensive to rent, I don't think the number of aperture blades in the lenses chosen is due to a budget constraint. Are there any reasons in general why there are these big-bucks lenses with such a visible visual "flaw"?
In stills photography lenses I recall at least a certain Leica Summilux 35mm model which also chose to use octagonal arrangement, which occasionally can result in an "ugly" bokeh, all subjective of course.