Orange Coloured Stains in Diaper. Be?

Hi doctor, My nephew is of 7 and a half month old baby boy.He was 2.8 kgs when he was born.There were any other health issues since then..Vaccinations are all done till date..but somehow missed Vitamin K that was supposed to be given in the initial days of his birth..Now..Since almost a month he is being breastfed mostly..and daily once he is being given either boiled carrot or an apple puree or watermelon in a nibbler or cerelac rice or wheat flavours..and boiled water..we observed some orange coloured stains on front side of his diaper some 4 days back..again next day.it was not there.but today there is the same stain in his diaper..could you please let us know what it could be?we are yet to meet his doctor once we get the appointment..but we are worried..please suggest what it could be?attaching a pic of the diaper stain. Thank you, Rubeena