I was going to do some cad work in freecad, and noticed that it would crash whenever attempting to render a 3d scene with the error "/var/tmp/portage/media-libs/coin-4.0.0/work/coin/src/glue/gl.cpp:2354: const cc_glglue* cc_glglue_instance(int): Assertion `current_ctx && "Must have a current GL context when instantiating cc_glglue!! (Note: if you are using an old Mesa GL version, set the environment variable COIN_GL_NO_CURRENT_CONTEXT_CHECK to get around what may be a Mesa bug.)"' failed" , although this is fixed by running it with the QT_QPA_PLATFORM env variable set to xcb. I wasn't able to confirm if this is fixed in later versions of the software, so the addition of a patch may be necessary.
The issue you are describing originates in media-libs/coin: Bug 869686
*** This bug has been marked as a duplicate of bug 916386 ***
