I can confirm freezes and halt of process.
default MZ Core script used: 1.8.0, also tested oder version (1.7.0 and 1.4.0)
The freeze occurs just the moment a node grows to mature state.
and an addition: setting low growth time (below 1k frames in my test) causes syntax error in growth-time to be undefined for whatever reason. - not a major issue as I think no one wants to regrow things within seconds except for testing purpose.
I will also try in a clean project without any other scripts later to find out if there might be some duplicate declared names causing this side effect.
Update while writing this:
Maybe identified VisuStella core as the impact on your script. Will have to check further for the function causing this hangup.
In a clean project only running your scripts, it works pretty well ;) - also tested with mz core 1.8.0 without issues
Something that did not work in a clean project anyway: profession exp not added and professions don't seem to work as a requirement maybe misunderstood smth here - idk