[2.0.28] Dropped frames only when Factorio is focused, but showing 60 fps/UPS

[panko]

Since 2.0.28, Factorio is dropping large numbers of frames. This did not happen in prior versions.
Strangely, this does not happen when the window is not in focus.
It happens on all savefiles, including brand new games and even the menu simulations.

System specs:
Windows 10
Intel Core i7-8700K 6-Core 3.7 GHz
nvidia GTX 1080 Ti
16GB (2 x 8GB) 3600 MHz

nVidia drivers: 566.36

Video

lag-trim.mp4

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Log

factorio-current.log

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