Yah, as mentioned above, once you fret any note, a pickup located according to the harmonic nodes will no longer be under its node.
However the 1/4 length (24th fret) location is an accepted standard.
On 24 fret guitars, the neck pickup has to be a bit closer to the bridge resulting in a brighter, slightly thinner tone.
Some players prefer the neck tone of 22- and 21-fret guitars over 24-fretters because of that.
Though there isn't a standard so universal for bridge pickup location, placement is equally critical there.
Perhaps even more so because of the brightness of the signal in bridge position.
Forty years ago I moved the bridge humbucker on one of my Floydcasters about 1/4 inch further away from the bridge.
I was amazed at how much difference just a few millimeters made in the sound.
Warmer, fuller, smoother, and possibly a tad more output too, I think.
It really transformed the voice of the pickup.
Poor quality pic but you can see the small gap alongside the bridge pickup:
