Why Can the Recording Be Normal After the Phone Screen Is Locked During the Allocation Process of Instruments?

When I use Instruments to record Allocation, the phone will display a dialog box indicating that the phone is unlocked when the screen is locked, as shown in Figure 1. When I have started recording allocation and lock the screen 10s later, the allocation can be recorded normally. For details, see Figure 2. I want to know why. Start recording for 10s and lock the screen on the device. The recording can be performed normally. What is the principle of this?