After the discussion here (https://en.numista.com/forum/topic48243.html) a new year line for 1981 was added to KM# 69a.
So if you have a 10 Seniti 1981, check the weight of your coin, check if it's magnetic or not, or look at the obverse design. It's possible you have to move your coin from KM# 69 to KM# 69a.