City of Aspen Press Release:
Mayoral Vote Tally Corrected; Outcome Stays the Same
http://theredant.squarespace.com/storage/TallyCorrectedTB.pdf

This should be a wake-up call to all who are working on or using computer
programs to count STV ballots.

It is essential that the algorithm in the program implements the specified
election rules exactly. Ideally, all programs used in public elections should
be independently certified against the relevant election rules before they are
used.

The feature that reportedly caused the problem here is specific to the Cambridge
MA election rules for multi-seat STV elections. This feature is of no relevance
for single-seat STV elections and should not have been enabled for a count of a
single-seat election.