I didn’t notice this before since I don’t read the solicitations materials online, but here’s the cover of Ultimate Comics Spider-Man #15 that Marvel put online:
And here’s what they put in the actual Previews magazine:
I always thought those color-coded bars on the side of every. single. page in Marvel Previews were excessive. I doubt this was anything other than lazy page layout, but that is an unfortunate bit of accidental censorship.