Hello,
Either you are using Android Flamingo with Google Services or Bluestacks, I have seen that by default they use the camera of PC even switched on to the ivcam camera.
Then for other software like bandicam or Obs this problem doesn't occur.
It seems that you need to set up on a PC without camera then running ivcam software will not run by default the camera of PC and then I think it will be same case even if you install USB Camera as by default it uses those of the PC.