I noticed this too; started up about a week ago. I copy from mainly PHP tags and I don't believe I loose the linefeeds, I'll have to try on code ones too.
Its a little annoying I have to admit yeah. I would suggest that the way to fix it is to either remove it completely or make it so the paste doesn't apply that line if pasted back into codingforums.com. I'm not sure where it comes from, so masmedia is looking into any of the new functionality added to see if it could include that.