What happened when the security camera repeated what I said after I spoke?

The security camera repeated what I said for several reasons.

First of all, the first reason may be holding a mobile phone and talking next to the camera, and the radio and power amplifier have echoes;

It is very likely that your pickup is connected to the back-end equipment, such as the mic interface of the network camera, and the normal pickup is connected to the linein interface, so you need to adjust the camera software settings.

There is something wrong with the selected power supply, and the voltage is insufficient. Using switching power supply may cause poor sound quality. Linear regulated DC power supply should be selected.