I don’t know what Apple is doing with audio timing in macOS High Sierra, but they have serious quality control issues in this area. See my post on Avid S3L-X, AVB, and macOS High Sierra for other troubles I’m having.
When Apple released 10.13.2, my Audioquest DragonFly Red started having strange issues. Similar to the clicking issue with AVB, I was having strange timing issues that sounded like phasing, almost like the individual waveform samples were being triggered at a different clock rate than the audio device. It wasn’t constant, but frequent and annoying enough that I gave up using the device. I wasn’t the only one having the issue.
In any case, 10.13.4 fixed my Dragonfly issues, so I’m again happy.