Load all modules implementing a behaviour in escript

I’ve created a small project to demonstrate the problem, see GitHub - elvanja/escript_testbed · GitHub. One funny thing I noticed is that running it as a mix task also doesn’t work, unless I change one of the scenario modules. In that case, that module is compiled, and mix task is able to find it. But, if there are no changes, there’s also no result. So even in mix tasks I’m not getting the code in lib unless directly specified somehow.