Mono hardware output assignement

For those of youguys that are familiar with OTB mixing, and use it regularly, i noticed that REAPER had an odd behavior while assigning tracks to mono outputs... I am currently working with an RME card, and when it comes to mixdown via the mixer and redirecting a track/ bus to a mono output e.g BASS to output 5, i still have to pan this channel hard left -totalmix- to avoiding it bleed in output 6 in the out of the card, thus in the mixer ... Is this a normal behaviour or there is something that i miss in tweaking REAPER properly? As another example, i don't have any problem at that time with Logic on this side. I still think it's an issue that is shared by both MAC and PC version of REAPER. Is anyone can bring up his thought on this, or am i pointing something uncovered at the time. Cheers

I don't have this problem... e-mu 1616m, win XP (x86) I have set those output channels in my e-mu patchmix as mono. Have you turned off master/parent send on the channels you are sending outboard?

Hi, Of course master/ parent send is off... 3.45 here Any clues?