Ok, a few data points for this thread:
Tier: Platinum
Date: Jan 8 2019
Flight: WS 585
Route: YHM-YYC
Upgraded: (Y/N): Y
Original Fare: Flex
When?: T-25
Tier: Platinum
Date: Jan 8 2019
Flight: WS 1570
Route: YYC-DEN
Upgraded: (Y/N): Had to call in to platinum line to force an upgrade at T-24 for some unknown reason
Original Fare: Flex
When?: T-24
Tier: Platinum
Date: Jan 10 2019
Flight: WS 1571
Route: DEN-YYC
Upgraded: (Y/N): Y
Original Fare: Flex
When?: T-35
Tier: Platinum
Date: Jan 10 2019
Flight: WS 584
Route: YYC-YHM
Upgraded: (Y/N): Y
Original Fare: Flex
When?: T-35