If exec is added manually in front of process command line, adding it automatically breaks things.

Working example in 3.2 version:

melody run https://gist.github.com/mariusbalcytis/65b5799db0c04f0f82eb97c2be77db40

Stopped working in 3.3 version:

melody run https://gist.github.com/mariusbalcytis/5b28910592485b69fe9a26b926913afb

I'd say that this could be implemented in quite a lot of places - in fact, if PhpProcess class would be in different component, it would have stopped working, too (as it added exec manually).