I thank you both for your compliments. And just for that, I'll bite. Remember, this is sight unseen:

No, I don't think there's anything inherently wrong with the nut, the frets or anything pertaining to the bridge. I doubt VERY strongly there are any inherent Fender QC issues in general, either. I know this is a popular retort in certain circles when a seemingly baffling issue presents itself. Notwithstanding, I'm more than comfortable ruling all the above out as Fender's lengthy track record boasts to the contrary. Having said this...

That fingerboard is saturated with oil. This seeps through to the truss rod, under the frets, etc. and tends to collect around any substances which do not absorb it; yes, I'm talking miniscule pooling. Couple this with the guitar being acutely 'traumatized' by all those adjustments, make for a very unstable instrument for as we know, any new instrument needs to 'cure' and continue drying out/settling in, some taking longer than others (as is typical). Unfortunately, this guitar has been subjected to extremes of the exact opposite at the absolute worst time in the guitar's history, its beginnings. Further, placing it in a working rotation, the guitar is simply not (yet) up to it. This, by necessity includes constant changes to the guitar's environment as it does not stay in one place. Lastly as the rather immediate, recurring symptoms of instability always come back to the middle strings buzzing about, this leads me to believe the collective bridge saddle radius does not adequately match that of the fingerboard. And don't kid yourself, every time a new set of strings go on, even the exact same brand/gauge, there is minute shifting of the block, bridge and neck; again, more undue and destabilizing trauma which this guitar surely does not need at this point.

If you haven't read between the lines here, this guitar should literally be left alone in a most favorable, single environment for a prolonged period of time, being played briefly, maybe once a week as is, regardless of what is right and wrong with it. What kind of time are we talking here? Again, without the guitar in front of me which also means I can't even see what the current setup looks like, I must refrain to recusing myself.

As always, the above is merely IMO where YMMV.

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Thankyou for input Martian. I hear what your saying. I'll be leaving the lemon oil alone and return it to the shop and explain my concerns and get it all checked over again. Following that. Other than playing it I'll be leaving it alone, including the strings for as long as possible. Thanks again Martian for your input.

You're quite welcome. The use of lemon oil on rosewood should be considered in the category of, "If it ain't broke, don't fix it." Typically, rosewood doesn't need any regimented oil treatment(s) unless it either shows blatant signs of, or is known to be, in need of (re)conditioning. See, unlike say, ebony, rosewood is by comparison a pliable wood. This alone is verification that it readily absorbs for example, body oils (from playing) and ambient moisture in general. Another ready proof of this is it's comparative sonic properties among the other woods typically used for guitars.

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Great info. Thanks again.

And just to add. When I measured the neck relief a couple of days a go it was at .014". Checked it again earlier and it had gone up to .017". I may been wrong but it certainly seems like something is moving out of whack. That last time the truss rod was touched was about the middle of December.

You're welcome.

Evidently (and it's a good sign), the neck/board is contracting/drying out. Let it continue to 'do it's thing', adjust nothing. Once any and all measurements have stabilized (and don't be hasty), it is at this point that ever so slight tweaking should begin in spread out stages. Again, continuing to allow the wood to firm up and all measurements stabilize, one tweak at a time. The key word here is, PATIENCE. Remember, "Slow and steady wins the race!"

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Still looking for that One Guitar To Rule Them All since 1964...
FSR Fender 60 Anniversary Strat HSS MIM, Gibson ES 335, Taylor 555, Ovation Custom Balladeer-12, Baby Taylor, Fender Princeton Chorus (stereo), Fender Champ 600

Both times he looked at it I recieved it back and it played lovely. Perfect for me. I always speak to him face to face with any guitar he has looked at of mine. It's the constant return of the buzz that's the problem. Not that the buzz can't be cured initially. I may be wrong but I suspect that if the neck needed a shim, a good set up wouldnot be achievable in the first place. But that is not the case with this guitar.
And the buzz is all the way up the neck.