ULA is vocal about its 100% mission success as of May 2025*. But Vulcan is a new vehicle, and it is likely to fly well over 100 times over its lifespan.

Will Vulcan ever suffer an anomaly resulting in the loss of a mission?

Vulcan will probably fly well into the 30s, if not 40s. I've set a resolution date of 2035 and assume it will regularly be pushed out. Assuming Manifold is still around, I'm unlikely to be there to do this or eventually resolve the question; in that case, I encourage adoption!

*Atlas V very nearly failed twice, once without affecting the payload and the other time resulting in an off-nominal insertion, but in these cases ULA - and more importantly, the customers - declared success. In the off-nominal payload insertion case, the satellites were able to reach their intended orbit through their own power; if they hadn't, or if the NRO had declared the mission a partial or full failure despite the satellites being able to save themselves, I would consider it a failure.

Another example: the Vulcan Flight 2 SRB nozzle "observation" didn't affect payload insertion at all, and so is not considered a failure for the purposes of this market.