Playing with a phone tuner app ( Da Tuner - rather good ) - I was a liitle phased by my G string on the first torres guitar I made ( and regularly play ) showing errors in cents up the fretbord of up to 18 sharp etc.
With the string spot on at the 1st = 12th was 18 sharp - and various other frets all up the board were all over the place !
( this was not the tuner app - as I confirmed it with my other tuners. )
Strangely - the harmonics at the 12th on the G still seemed fairly good compared to the 12th fret ?
These were EJ46 - and been on maybe 3 months ? Yes they were looking like they needed changing ! It did surprise me though, how bad they had become in terms of intonation.
A new set EJ45 and all is as normal - all the way up the frets. It convinced a cheapskate like me that nylon strings really do need changing fairly regularly !