This is a special dividend, a one-off dividend according to the board and as such can be misleading if included when calculating the dividend yield.
Best practise would be to pick your preferred div yield and then add the special div to the resulting price to arrive at your preferred buying price.
Having said that, Safaricom is a Great stock, with a promising future and no proper competitor for now and hence should be in every investors basket.
@SufficientlyP