Hi Sir,
I found that when the circuit is connected to VIN2 (VIO_1V8), the chip power is powered on, and VOUT outputs, when VIN1 (3V3) is connected, because the PR1 pin changes from low level to high level, VOUT outputs normally, but when VIN1 (3V3) is disconnected, VOUT will suddenly power off and then power on, as shown in the following waveform, this problem will cause our equipment to restart or power off