305 voters, 5 candidates.
Counts: A = 50, B = 52, C = 100, D = 52, E = 51. A is eliminated by a margin of one vote. B gains 49 votes. B = 101, C = 100, D = 52, E = 51.
Then E is eliminated by a margin of one vote. 50 votes transfer to D.
B = 101, C = 100, D = 102. C is eliminated by the margin of one vote.
B = 152, D = 151. B wins by one vote.
In EVERY ROUND, the election was within one vote. That means expensive recounts and lawsuits.
D is a spoiler. D drew away votes away from the centrist C. If two members of the DE party had instead artificially ranked C top, then D would get eliminated and then C would win over B by about 200-100. This tactical voting would have given the two voters a better outcome.
C was preferred over every candidate by about a 2:1 ratio. And the D party, which has been branded as a SPOILER, may drop out. Meanwhile A and E were too extreme to have any chance, so we end up with two party domination between B (and maybe A/E, until they get too greedy and become a spoiler again) and C.
The D voters were tricked in another way. The second place votes of the DCEAB voters were not counted because their first vote was still on D at the critical moment that eliminated C. IRV ignored their second place votes while giving notice to other voters’ second choice candidates.
The election is equivalent to this:
IRV never examined more than two layers in. Annoyingly, C was even ranked first or second by a majority of voters, but still lost.
Yep, just about every flaw that real world voters care about, happened.