If the fretwire is seated properly…
Concerning possible dead spots from a guitar’s acoustic properties
When the frequency of a fretted note matches the natural resonance frequency of the guitar’s neck and body, and the resulting vibrations interfere destructively, it can cause a dead spot. This dead spot leads to less energy in the vibrating string, which reduces the sustain of that particular note. The energy that would normally sustain the note is instead absorbed by the guitar’s neck or body, leading to a quicker decay in the sound.