  We present new SO(4)-invariant and non-supersymmetric instanton solutions for
the conformally coupled m^2=-2 and massive m^2=+4 (pseudo)scalars arising from
a consistent truncation of 11-dimensional supergravity over AdS_4 x S^7/Z_k
when the internal space is a S^1 Hopf fibration on CP^3, and we consider
backreaction. In fact, the bulk configurations associate with (anti)membranes
wrapped around mixed internal (and external) directions, which in turn probe
the Wick-rotated or skew-whiffed background, break all supersymmetries as well
as parity invariance. From near the boundary behavior of the closed solution
for the coupled bulk (pseudo)scalar, we get a marginal triple-trace deformation
with mixed boundary condition (valid also for the bulk massless m^2=0
(pseudo)scalar, raised when considering the external space backreaction, with
Dirichlet boundary condition) and as a result, the corresponding boundary
effective potential is unbounded from below and causes an instability because
of the Fubini-like instanton. Presenting dual effective actions, we see that
the boundary solutions and counterparts realize in singlet sectors of
three-dimensional U(N) and O(N) Chern--Simons-matter field theories. In
particular, we use versions of massless and mass-deformed regular and critical
boson and fermion models, find instantons and confirm state-operator
AdS_4/CFT_3 correspondence and also Bose-Fermi duality at the level of the
solutions. In addition, we discuss on relations of our setups with Vasiliev's
Higher-Spin theories, deformations of the Aharony-Bergman-Jafferis-Maldacena
model and other related studies.
