A query about ranking

Not that it matters much but i think there is a problem with ranking system ... Harshad's ranking was 15 last week ... this week first it moved to 14 but still had a down arrow ... later it was changed and his last week ranking is now shown as 14 and current week 15 ... when in reality harshad's ranking was 15 last week and week before that it was 12 ... it was not 14 as it is currently showing ... even if its 15 for this week too then as well there should have been the yellow arrows and not red one because 15 was his ranking last week too

This has happened before too with his ranking so thought of asking because it might be affecting other rankings too