I'm having this same problem using magic loop, but I've never had a problem with laddering when using dpns or regular circular knitting.
I'm trying the 2 at a time socks on one long cir and only one side of the same sock is doing this! I don't understand why 3 of the other sides are fine, except for just this one side. And I'm tightening up those stitches, so I don't understand why it is doing this.
~Knit for Charity~
"that their hearts may be encouraged, being knit together in love" - Col. 2:2
TXMcKnitty on Ravelry