For real numbers, the operators ' and .' give the same result.
xR = 1:10;
y1R = xR'
y2R = xR.'
For complex numbers, they don't.
xC = complex(1:10, 10:-1:1);
y1C = xC'
y2C = xC.'
See the documentation for either transpose or ctranspose for a brief explanation of the difference between the two.
I suspect your deltaeta is complex.