I'm not 100% sure what your asking here, but by nature the bead of a 6011 looks like crap as compared to, sat a 7018. In other words where a 7018 will have a nice rippled appearance, a 6011 will typically have a coarse rippled appearance like it was run too hot. Too a 6011 is a deep penetrating rod that tend to make it seem like your welding 'hotter' than another rod would at a comparable amperage setting. On top of both of those you say you were also welding uphill, on lighter guage material, and if that isn't done just right the edges of the weld would probably be a bit undercut (ie there's a shallow crater along the edge of the bead).
In the end, and I am still guessing here, that the deep penetration characteristics, the 'not so pretty' bead that the rod typically leaves, and possibly a crater left over, are probably the things causing the issue your describing.