There is also a threat of Typhoon Fitow expected to bring torrential rain and gusty winds over the weekend in Tamsui.
Rahil Gangjee, one-over for the front nine, dropped three bogeys between 11th and 15th before posting a birdie on 18th during his round of 75.
At a total of six-over 222 he was tied 22nd, down five places from overnight 17th.
Shiv Kapur had a tough time with a card of 80 that included nine birdies and just one birdie. He is now 13-over for three rounds and in 50th place.
Overnight leader Sam Cyr of the United States slipped to second place after signing for a 73 on a day where only four players managed to break par at the Taiwan Golf and Country Club.
Bangladesh's Siddikur remained in contention for his second win on the region's premier Tour when he posted a 71 to share third place with Thailand's Panuphol Pittayarat who carded a 72 at the richest Asian Tour event to be staged in Chinese Taipei this season.