A legal requirements to preserve the integrity of authorship and copyright information follows from article 6bis of the Berne Convention (about moral rights). In the USA, U.S. Code § 1202: "Integrity of copyright management information", is quite explicit about this - https://www.law.cornell.edu/uscode/text/17/1202 - but similar provisions exists in the local laws for most Berne signatories. Since preservation of attribution, etc. is a legal requirement, it cannot be removed by a license or a FAQ (and for the record: CC BY does not remove this legal requirement). It applies universially (i.e. does not depend on the license used).
This means that if Bob adapts Alice's work and Carol adapts Bob's work, Carol has to attribute both, unless one or both request to be dis-associated with Carol's work by having their respective bylines removed.
When only three people are involved, the reasonable way to attribute is to list all three of them.
However, when the list of contributors become much longer than this (e.g. you build on a wikipedia article with hundreds of individual contributors where the contributions over time have been entangled), you may find an alternative reasonable manner to provide lawful attribution. For example, you may credit "Wikipedia contributors" with a link to the article's history page where the byline of each individual contributor is listed.
There is a page about attribution best practices on the CC wiki that provides some helpful examples about how to attribute in a reasonable manner.