All tracks suddenly have low volume, the meters are also visually much lower

Cubase
1

A strange behavior in Cubase Pro 15 started today, and I can’t find the cause. It all worked fine yesterday, and when I opened projects that were mixed to peaking at -6 dB and mastered to -9 dB RMS, they sound quieter today, and like unglued… And the master compressor doesn’t even get any reaction because its input volume is too low. The whole mix doesn’t peak at -6 anymore, but -12…-15, and with the master chain enabled, the RMS is around -12…-14.

I know what’s not causing this: channel faders, Q-link, channel gain, CDC (Constrain Delay Compensation), master fader, Control Room dim or volume.

The problem is somehow global. All the projects that I open today have this problem right away, without touching anything first. The biggest mystery is the meters themselves, they are visually much lower, they peak less. Just like all the plugins got magically lower output volume overnight.
I even updated Cubase to 15.0.21 and it didn’t change anything about this.

2

Please don’t tell us that you used VCAs.

3

No way. New fresh projects are also quiet, even when I start a clean empty project, not from any template. I remember how ReFx Nexus always spiked a lot higher with its default sound when the plugin is added. Now its sound spikes way lower than that, more like around -9…-11 dB.