NextGenCore::createCollection() allows the creation of an unbounded array of generative scripts for the collection: NextGenCore.sol#L138.
But it doesnt allow updating scripts with index 999 and 1000, as the updateCollectionInfo() function overuses the index attribute to conditionally update other collection properties.
NextGenCore.sol#L240-L252
This makes it impossible to update those values, bricking the contract functionality.
The recommendation would be to refactor the updateCollectionInfo() function, so that it doesnt use the index for multiple purposes, and allow the update of any element on the scripts array.
Another possible but not recommended solution would be to limit the scripts size to < 999.
