This is a ‘sleeper risk’ that almost always happens.  Who sabotages the project?  They don’t do it on purpose.  It happens because if you have the wherewithal to undertake an ERP project, you must be doing something right. Congratulations – the processes you have must work. But you will need to let go of some of them and embrace new ways of doing things to avoid going down the ‘functionality rabbit hole’. The trick is in knowing what current processes represent your ‘secret  sauce,’ and what can be changed.