Adding too much cheese can keep the the middle of the pizza from cooking properly, just like too much sauce or too many large chunks of vegetables with high water content. It takes a LOT of cheese to reach that point, but it is very possible when combined with the large chunks of vegetables.
It could be the cheese basically sealing in moisture from the sauce. Usually the cheese itself isn’t too wet, just oily, but if it completely covers a wet sauce and prevents that moisture from escaping, I think that would do it.
Adding too much cheese can keep the the middle of the pizza from cooking properly, just like too much sauce or too many large chunks of vegetables with high water content. It takes a LOT of cheese to reach that point, but it is very possible when combined with the large chunks of vegetables.
It could be the cheese basically sealing in moisture from the sauce. Usually the cheese itself isn’t too wet, just oily, but if it completely covers a wet sauce and prevents that moisture from escaping, I think that would do it.
That could be a factor as well. Keeping the moisture in would keep the crust from drying on top of the increase thermal mass of the cheese itself.