According to this press release, which I wrote:
...21 electors of the 93 were from outside Edmonton Centre but had voted there.
--in other words, we tried to identify people who appeared to have lived outside Edmonton Centre and voted within--
Almost all had received a voter information card listing a business address in Edmonton Centre. Further analysis indicated that the addresses of these 21 electors had been updated in the National Register of Electors based on information that they had provided to the Canada Revenue Agency or the Alberta Registrar of Motor Vehicle Services. Therefore, none of these electors wilfully or knowingly registered to vote in the wrong electoral district, and none were found to have voted twice.