The existing Higgs Characterisation Model cannot be used for certain processes (mainly ggH). The Bug report in the launchpad can be found here: https://bugs.launchpad.net/mg5amcnlo/+bug/1949450?comments=all
The authors provided a new version of the model in: https://feynrules.irmp.ucl.ac.be/wiki/HiggsCharacterisation
that is needed for MadGraph5_v3.X