It would be interesting to see how the error rate on the ranked-choice ballots compares to standard ballots. Having served as a poll worker myself, I assure you that it's normal to have a certain number of people fail to vote in a given race, and to have a certain number of improperly marked ballots. So, unless that rate has gone up a lot, I don't see the case for the confusion argument. Other than that, this seems like a lot of complaints from losing candidates. Folks I talked to who had voted in these elections were pleased with the ballots and with the results.

This article shows the problems with ranked choice voting system. It also includes a response from the company that provides this voting system. The idea that 10% had problems causes concern.

This blog post reads mostly like a news report, with good research and balanced interviews. In one section a previous work by the author is quoted as a first person opinion source, but the followup conveys counter-responses fairly well. His previous blog post on the subject also shows extensive research work.