My app runs great on 10.7.3, but is very glitchy on 10.6.8

Hello all. I have an app that runs as expected on OS 10.7.3 (which is the OS of the machine I’m developing on), but is very glitchy on 10.6.8. Anyone have experience building an app that runs nicely on the largest range of mac OSs?

Here’s how things should look:

Here’s how they actually do look (note: this is a photo because the glitch doesn’t show up when I take a screen shot)

I built the binary using 10.8 as the base sdk, and 10.5 as the deployment target.

Here’s some stuff I’m calling:

glHint(GL_LINE_SMOOTH_HINT,GL_NICEST);
ofEnableAlphaBlending();
ofClear
ofRect
ofTTFCharacter

Any red flags here? Do things generally work fine across different version of OSX?

Thanks, and happy 2013!

-Morgan