I have a very large patch with a couple GL scenes reading to 3 different gl.cornerpins. When I output_texture from jit.world to the syphonserver I only get one cornerpin that presents a scene. The problem goes away when I read the cornerpins to a node and connect to syphon from there. And it also works fine when I use GL2.
I have done my best to recreate a very tiny example patch. This patch works with GL2, and not with GL3. I have updated syphon and seen the recent article regarding GL3 and syphon. I'm probably missing something, so eager to learn about proper contexts and stuff, but given the newness of GL3 maybe I caught my first bug ☺️