Maybe a rogue string

[Bain]

So I changed my strings from d’darrio EJ 16 , 12,53 to newtone 12 54 all my intonation is good from open strings to the 12 fret except for the A string at the 12 fret it is sharp 5 cents , what is going on here ? Is it a bad string ? Or something else I should worry about, never had this before , who to ask but here .
Other info the A string starts to go sharp from the 9th fret only slightly tho until the 12, when it is 5 cents sharp but after that it is back in tune , so is it a bad string or what ,
I know I am a little paranoid with this but it is annoying I don’t even play at the 12 fret .. thanks guys , oh the finger pressure I feel is the same .........😳

[Russ C]

Yes, in my experience strings are capable of that and it's well worth eating into a new set to fix it.
I remember a Guitar Centre had 3 D45V's in stock and on one the 6th string sound awful. Instead of having the wit to say hey I'll give you (some ridiculously low figure) for this piece of junk and get it out of your life I said hey give me a new string and I'll fix it, and it did.

[Jim Owen]

Hi Bain,
It’s probably the string. The Newtone is round core; the windings May have slipped.

[Bain]

Hi guys thanks I,ll just buy a new set and see what happens I can’t be bothered to complain to them , there again they are only 40 mins from me ..........🙄