Why is this not Monster Level 82?

Corrupted does not automatically provide +1 level anymore. You have to look at the corrupted areas and find a mod on that map node that says “+1 monster area” or something like that and also have it irradiated. You also need a boss icon if you want to get the 7-8 points on the boss passive tree.

Corrupted or Cleansed maps can roll +1 to monster level, but if they do it'll show on the list of modifiers

If your build is strong, you have a lot of maps, can invest in them and you aim for high level maps you can go for the double corruption node for getting 16s to 17s. That is how I get my 6links and lvl20 spirit gems.

I think corruption no longer adds +1 to monsters level. I had this same thing happen earlier and didn’t understand it

So you dont progress too fast.