How many cases were there of vote-swapping in erstwhile elections? We check

In this year's presidential election, there were irregularities in at least respective PECs involving the substitution of candidates' votes. Reports of specified situations were included in election protests submitted to the ultimate Court. Their investigation is inactive underway. And how did it look in erstwhile years? We found 1 case of specified a protest in the SN's resolutions on the last 3 presidential elections. It was explained and described in detail.