The problem is, that there are many entites in the map (espacially trees and gras).
With max_enities = 2000 there is no problem in runtime, but as said before, publish doesn't look at the script and just sees, that there are much more entitys in the map as the nexus would allow and crashes WED.

Maybe 400 was a bit to much, I just doubled it as I recognized it was the problem (don't ask me, why I came to the stupid idea this was the problem) and then it worked.

But newertheless I have the similar RAM sizes as you got... really strange.

I'll try with a bit lower nexus in the next version, so I hope that'll fix it...