How many cases of vote swapping in erstwhile elections? Checking

In this year's presidential election, there were irregularities in at least a fewer regional electoral commissions involving the replacement of candidates' votes. Reports of specified situations were included in electoral protests directed to the ultimate Court. They're inactive being considered. What did it look like in erstwhile years? In the resolutions of the SN on the last 3 presidential elections we found 1 case of specified protest. It has been explained and accurately described.