  We investigate in the Large Hadron Collider (LHC) environment the possibility
that sizeable interference effects between a {\sl heavy} charged Higgs boson
signal produced via $bg\to tH^-$ (+ c.c.) scattering and decaying via $H^-\to
W^- A\to W^- b\bar b$ (+ c.c.) and the irreducible background given by $bg\to t
W^- b\bar b$ topologies could spoil current search approaches where the former
and latter channels are treated separately. The rationale for this comes from
the fact that a heavy charged Higgs state can have a large width, and so can
happen for the CP-odd neutral Higgs state emerging in the ensuing decays well,
which in turn enables such interferences. We conclude that effects are very
significant, both at the inclusive and exclusive level (i.e., both before and
after $H^\pm$ selection cuts are enforced, respectively) and typically of a
destructive nature. This therefore implies that currently established LHC
reaches for heavy charged Higgs bosons require some level of rescaling.
However, this is possible a posteriori, as the aforementioned $H^\pm$ selection
cuts shape the interference contributions at the differential level in a way
similar to that of the isolated $H^\pm$ signal, so there is no need to reassess
the efficiency of the individual cuts. We show such effects quantitatively by
borrowing benchmarks points from different Yukawa types of a 2-Higgs Doublet
Model parameter space for $H^\pm$ values starting from around 200 GeV.
