  Based on a vector triplet model we study a possible failure of dimension-6
operators in describing LHC Higgs kinematics. First, we illustrate that
including dimension-6 contributions squared can significantly improve the
agreement between the full model and the dimension-6 approximation, both in
associated Higgs production and in weak-boson-fusion Higgs production. Second,
we test how a simplified model with an additional heavy scalar could improve
the agreement in critical LHC observables. In weak boson fusion we find an
improvement for virtuality-related observables at large energies, but at the
cost of sizeable deviations in interference patterns and angular correlations.
