I've made some discoveries since my last post. For reference, my system had been running:
- Windows 7 (64-bit)
- Intel HD 4600 w/driver version 10.18.10.3907
I wanted to make absolute certain that I was running the latest driver, so I ventured over to the download center and found that I had been running 126.96.36.199.3907 (10.18.10.3907). The latest driver is 188.8.131.52.3960 (10.18.10.3960). Here is where it gets interesting. The download page (https://downloadcenter.intel.com/Detail_Desc.aspx?DwnldID=24348&lang=eng&ProdId=3720) for 184.108.40.206.3960 says, "This driver package contains version 220.127.116.11.3907 (10.18.10.3907) for Windows* 7/8/8.1." Which is incorrect. This is where I had tripped up. I knew that I was running 10.18.10.3907 (as reported by Windows) so when I checked the latest driver in the download center and looked at the driver version I was led to believe I was running the correct (latest) one. I was tipped off when I looked on my install drive and noticed the mismatch between the executable filenames for my installed driver and the latest in the download center.
After installing the latest driver my initial issue is resolved.