Is Mac hardware with the T2 chip vulnerable to the latest Intel CSME exploit?
Yes.  

I was curious about this also, so I tweeted at the security researcher who discovered the flaw, this was his response:   


  My understanding is that on Macs with T1/T2 chips, hard disk encryption isn't affected. I don't know whether they use IPT, but DRM is certainly affected. And of course CSME arbitrary code execution is possible even if T1/T2 present (can intercept usb traffic for example)