I am wondering if maxmsp is interpreting the alpha values from syphon differently than other syphon environments?
If I use the standard simple server as source, it looks the same in simple client, but in the jit.gl.syphonclient it looks much darker. Only by turning blendmode to 0 makes it look the same, but that just turns off the alpha channel so that is not ideal.
This does not occur with syphon sources made in max, so sending syphon from max to vpt for instance works as expected with the alpha information intact.
I had a user report the same alpha issue with sending syphon from his processing sketch to vpt. However for me, the included syphontest example works fine.