Why does Repeater give a different effect every time?

I know that I can fix the above problem by playing with the anchor point of the shape, but I don't understand why I get different results every time... Sometimes even when I apply a repeater to a copy of a shape I animated, the result is different. Everything is the same but the result is different. Sometimes it is really tiring to deal with anchor points all the time. I may even have to redo the whole animation from the beginning. What to pay attention to when using the repeater or before using it.