  In this work, we explore interesting consequences arising from the coupling
between a clean non-Hermitian chain with skin localization and a delocalized
chain of the same length under various boundary conditions (BCs). We reveal
that in the ladder with weak rung coupling, the nonHermitian skin localization
could induce a pseudo mobility edge in the complex energy plane, which
separates states with extended and localized profiles yet allowing
unidirectional transport of signals. We also demonstrate the gradual takeover
of the non-Hermitian skin effect in the entire system with the increase of the
rung coupling under conventional open BC. When taking open BC for the
nonHermitian chain and periodic BC for the other, it is discovered that a
quantized winding number defined under periodic BC could characterize the
transition from the pseudo mobility edge to the trivial extended phases,
establishing a "bulk-defect correspondence" in our quasi-1D non-Hermitian
system. This work hence unveils more subtle properties of non-Hermitian skin
effects and sheds light on the topological nature of the non-Hermitian
localized modes in the proximity to systems with dissimilar localization
properties.
