No: the what3words system is fixed. As such, there is 100% certainty that all instances of the system running everywhere in the world will provide the same 3 word address for the same location. You don’t have to worry about anything changing. It is fixed already and will stay that way.
Occasionally we have languages in beta - when that is the case it means we are testing and gathering feedback, so it is possible that a handful of words will change when we come out of beta and officially launch the language.