(HELP) Only mono signal using Overbridge?

Hi friends! Im new on this world I bought my A4 1 week ago and well Im tring to use in ableton by 4 channels 1 per Voice, the problem is that if I use in Mono I can use in that way but when I put Stereo Channels only sound in one size on voices 2 to 4 and in the voice 1 always listen the other channels.

Sory about my english I know that is the worst but im going to Improve