After upgrading to the Yamaha Steinberg USB Driver V2.1.5 for Windows, Cubase 12.0.60 realtime audio playback basically became unusable (even after setting buffer size to the maximum 2048 - it usually runs fine at 256 for me).
That driver revision also kills audio playback in SoundForge V17.
Rolling that driver back to V2.1.4 fixed both the Cubase and SoundForge problems, so it’s clearly that revision of that driver that’s the issue here.
TL;DR: stay away from V2.1.5 of the Yamaha USB Driver!
I tried filing a bug report with Yamaha, but gave up after not being able to find a way to contact Yamaha for a bug report for that driver on the Yamaha web site.
So I’m hoping this post will catch somebody’s attention at Yamaha/Steinberg to fix this bug. FWIW, this is on Windows 11 (latest patch level), with a Yamaha TF1 as my audio interface.