After dealing with the extremely annoying four-minute wakeup wait for a couple of weeks, I thought 2019.12.1.2 had taken care of it. Until yesterday, when it happened again. I (again) contacted tech support, and got this response: "The firmware version containing improvements for this issue is not available yet."
It sounds like this doesn't affect everyone, so of course that makes it harder to diagnose and fix, but it really needs to be a higher priority. For those of us experiencing it, it's a serious problem.