When running the evas gl tests in elm_test, and presumably any code that uses evas_gl, the api setup and extension query stuff seems to be done before the context is properly set.
the glesv2 path doesn't care and just YOLOs with the currently set gl context, which appears to work ok
the glesv3 path checks that a context has been "properly" assigned, fires an ERR, and fails to initialize extensions.