On August 3rd 2009 there was a festival near my neighbourhood, the Taiwan Day Festival at Bobolink Park. The event itself is not widely known, I saw no advertisements or news about it, nor did a quick Google search turn up much about it. I did find this tweet by Ujjal Dosanjh though! It seems to be overshadowed by the bigger TaiwanFest that is happening from September 5-7th at Plaza of Nations.
The reason for the different festivals is because they are put on by different associations. This one is organized by the Greater Vancouver Taiwanese Canadian Association. The one at Plaza of Nations is by the Taiwanese Canadian Cultural Society.