While with first two columns when you press left arrow or right arrow. It shifts column, but there is a lag in shifting the column.
After some investigation I found out that the lag is almost equal to the ANIMATION_DURATION_MSEC macro defined at the top of qcolumnview.cpp. When I increased this value, the lag was very prominent.

With some investigation I found out that this code creates the problem.

// If it is already visible don't animate
if (leftEdge > -horizontalOffset()
&& rightEdge <= ( horizontalOffset() + viewport()>size().width()))

{ d->columns.at(indexColumn)->scrollTo(index); d->_q_changeCurrentColumn(); return; }

in my scenario i found out that the first condition in if was coming out to be 0 > -0, thus failing and animating the scroll value when it shouldn't.
for me changing leftEdge >= -horizontalOffset() solved the issue. But I haven't looked at a lot of code in this file, I don't know whether this is the right approach to fix it.