I'm developing a project based on a Raspberry Pi 3B+ which utilizes an original Raspberry Pi Camera module. I'm powering the RPi from a 12V 4-cell LiPo, brought down to 5V by a power distribution board, to which I connnect the RPi via a usb cable. No devices other than the camera (which is connected via the CSI interface) are powered from the Pi itself - it only has 4 PWM channels connected, SDA & SCL, one gpio to read from and 4 Tx/Rx.
The problem is that when I run my program (which simply reads the video stream from imutils's PiVideoStream) and the camera module activates, the RPi's red led starts to blink, which, as far as I know, signalises voltage drops. Anyway, the camera works fine, I can obtain the data, but CPU temperature slowly begins to rise. As soon as I turn off the program, the camera turns off as well (judging by the camera's built-in led) and everything is back to normal.
Is there any way to fix this? And how is it even possible that an RPi with an official camera module causes voltage drops?