You do not need a jit.window at all for OpenGL and Syphon to work. You can render to a jit.pwindow or use an invisible window for a context. There are plenty of solutions to not have a visible window in Jitter and use OpenGL.
As for your bug, can you test this version, see if it works for you (it is also Max 6 compatible). This is the first i’ve heard of that bug. If you can repeat it with the version below, please post a patch demonstrating the issue, along with hardware specs. Thanks.