  Iterative decoder failures of quantum low density parity check (QLDPC) codes
are attributed to substructures in the code's graph, known as trapping sets, as
well as degenerate errors that can arise in quantum codes. Failure inducing
sets are subsets of codeword coordinates that, when initially in error, lead to
decoding failure in a trapping set. The purpose of this paper is to examine
failure inducing sets of QLDPC codes under syndrome-based iterative decoding.
As for classical LDPC codes, we show that absorbing sets play a central role in
understanding decoder failures. Raveendran and Vasi\~c initiated the study of
quantum trapping sets, where beyond the classical-type trapping sets, they
identified rigid symmetric structures (a.k.a symmetric stabilizers) responsible
for degenerate errors. In this paper, we show that this behavior is part of a
much more general phenomenon that can be described by the absorbing set
framework.
