I have to say that line calls are worse when I play mixed doubles (I'm a new NTRP 4.5, so I generally play 8.0 and 9.0 mixed doubles). My female opponents, and my female partners, often make line calling errors. I sometimes have to overrule my female partner in mixed doubles.
I really don't know why that is. Maybe it's because the female players aren't used to the faster pace and/or increased spin, and assume shots will be out, when in fact they dip down and land on the line.