When i slice my mesh made of 2 stl’s, preview shows well 2 colors output.
But when launched, my printer only use first head (right one).
For info, i can well, for single color object, use either first or second head.
I have the same issue here : sometimes the repetier jus don’t wants to print with two heads.
If it starts heating the head #2 then it will only print one colored and layer-shifted bad print. Despite a good slicing preview. When repetier does this to me, the only solution I’ve found is to quit repetier and start it again.
The two-heads printing seems more unstable than the single head printing. Sometimes I have a shift of 3-4mm in the middle of a well-started printing… Using only one head I never had that kind of issues…