I do not know the addons you mentioned, but check the sample resolution of the FBO.
This is some code that I have around in an old project
settings.numSamples = 4; // try 8 if your GPU supports it.
settings.useDepth = false; // set it to true if you are going to use meshes and need the depth, otherwise false is ok for raymarching
settings.width = ofGetWidth();
settings.height = ofGetHeight();
aw its completely my bad, I thought I had tried different versions of GL but I hadn’t. It works fine with GL2 but not with GL3.2 the dev mentioned “Add support for ofGLProgrammableRenderer with version 150 shaders” in the todo list, I’m really sorry for wasting your time