It’s not. plugin is a special global intended for plugin scripts available in its environment when the plugin initialises during a Studio session. If this was the issue, the error message would be different - mentioning something about trying to access an unknown global.
nevermind. what happened
what was wrong was that team create currently doesn’t work for publishing games (at least for some people)
for more info check this post.
This bug was reported over a year ago and I doubt this is the case. Did you perhaps mean that you saved your game instead of publishing the latest version and therefore the changes did not save? This, or if you had collaborative script editing enabled, did you forget to commit changes?