Assuming your bike has the same M 543 crank as the 2013 model, I wonder how the spindle got scored. It should always rotate in unison with the inner bearing race and could only get damaged if the bearing seized solid and the spindle slipped against the race.

That "weep-hole" looks like it is completely covered by the bb cup's threads so it shouldn't be a leak source. Also, there is an O-ringed tubular shield that should be part of the bottom bracket (part #9 in the Shimano tech document, see below). Was it installed?

http://techdocs.shimano.com/media/te...9830625624.pdf