Syphon output gliches

Hi there

I’m trying to use ofxSyphon with openframeworks (latest git build) on OSX (10.12.6)

After some configuration teething troubles it is basically working, but I’m seeing output “popping” from it’s correct scale to a bigger scale and back again erratically, making it unusable.

I’m using openGL 2.1.

Just wonder if anyone has seen this before I delve into whether syphon framework is up to date etc.

Tim