I booked a 3-leg one-way flight on .bomb on CO/UA/UA metal. I'm a 1P and was upgraded on the second leg at 72 hours. (As a CO Gold Elite I'm still waiting on the first leg to clear with 17 seats available in F - what's the hold-up CO? *grumble*) Anyhow, the clearing of the UDU upgrade on UA caused a "flight change" alert in CO's system and now when I review the reservation it says I am unable to check-in online. This is troubling for a number of reasons: 1. It is a 5:30am flight. Checking-in online, up to 24 hours in advance would save me precious time when arriving. 2. Several promotions come around that reward you for using mobile boarding passes. If using cellular and mobile devices to check-in and scan boarding passes is the green and rewarding way to go, this behavior of ticket changes makes you ineligible for those bonus promotions and time saving queueing at the airport. 3. Now that my ticket has been "changed" in CO's system I am not assured my place as a Gold Elite is maintained in their system for an upgrade on the first leg. It seems like now my only shot at a confirmed upgrade (again, we're 63 hours out with 17 seats in F still available) is to wait until the upgrade clears at the gate long after upgrades are sold at kiosks to other passengers at check-in. Has anyone else experienced this sort of thing and do you know of ways to avoid this in the future? I've called CO Elite desk and they weren't able to confirm a F upgrade or remove the flag from the reservation allowing me to check-in online. Frowny face.