I think this is a very natural thing to want to do. Suppose you start with a 100-line configuration, and then wish to make line 30 environment-specific - so you add an 'environment' block. Then you decide line 70 needs to be customized too - you add an environment block there. This is the natural, and seemingly obvious thing to do; but now your environment blocks are not working. This is essentially how I found this bug, and I was rather surprised to find that my first environment block was ignored - it is not at all intuitive.
If there are really a number of defects open around this behaviour, perhaps that is an argument for rewriting?