After noticing some play in the bottom bracket of my 2012 Cervelo R5 last week, I contacted our local VeloFix mechanic (I don't trust my LBS with this bike) to check it out and repair/replace parts as needed.
VeloFix showed up yesterday morning and proceeded to pull the cranks and BB from the frame before asking me to come have a look. I was gutted to hear, and see, that the BB shell has de-bonded from the frame on the drive-side.
The mechanic confirmed he's not a carbon fibre expert but he did not feel that the shell could be re-bonded or epoxied back to the frame with any chance of it being round or having long term success.

Ruckus Composites (there may be others as well) can do the repair. They replaced an ovalized BB shell on a S5 for me and it came out perfect. (My mechanic also said it couldn't be fixed.)

Original owner?
Should be a warranty job.
https://www.cervelo.com/en-US/warranty

Thanks asgelle & znomit will try the warranty route first (it is an 11 y/o frame after all).

I would think that your problem is a manufacturing defect no matter how old the bike is
Good luck

A person competent in working with the materials should be able to rebond the shell to the frame. After all, it is bonded from the get go. It's just a matter of possibly building up some carbon thickness, epoxying the shell to the frame, and making sure the alignment is spot on.

Might be a good excuse to buy a new bike/frame. It would certainly be more fun!

It most likely could be fixed. Also if it's a metal insert shell then who cares if it's "round" afterwards? most often there are secondary machining processes that need to be done anyway that would bring it into spec.