Possible cause of harsh mids?

There's a process for figuring out what is causing what. If it was a gain issue then the problem would be present every single time the volume got loud. That is not at all what was described. So it has nothing to do with gain. 

Likewise, if it had anything to do with the amp then it would be consistent. So the one simple fact that it is occasional tells us it can't be the amp. Then to test if it is what I said it gets a little harder. The way I know for sure is what I said, having heard multiple copies of the same record on the same table so the only thing left to explain it is pressing quality.  

Then having heard it and knowing exactly what it sounds like the next time it happens I know what it is. There's just no doubt any more. But that is because I went through the learning curve. 

sryeager, this is in no way an attempt to talk you out of buying a new amp. I would never ever try and talk anyone out of buying a new Raven amp. Or Decware, for that matter. 

Congratulations on the Soundsmith cart. It will be so sweet with a Raven, you will forget all about the occasional spitty pressing.

Thanks.  I hadn’t thought of that.  I’ll give it a try.  I think I may have kicked it up a notch way back when I got the phono preamp (Musical Surroundings NovaPhonomena) to bring the phono volume up to the level of the tuner and CD player.  The phono was quieter when I was using the preamp’s phono stage.

Does this Corea album exhibit the effect every time when played. How do other albums sound, any harshness?

There’s no mistaking sibilance, It’s a narrow frequency range in the upper mids or highs, the sssss sound. It's sounds different than distortion.
Is the loading on your phonostage set correctly for your cart?

MC has listed the most likely causes if this is a persistent problem.

Static like distortion and sibilance are two entirely different things. If the OP had heard this on other records he would have reported it. If his phono stage were overloading it would also do it on other records. I would tend to believe the OP and that it is a unique problem with this record, which means it is a problem with the record. If it walks like a duck and talks like a duck, it is usually a duck. In millercarbon's world it becomes an ostrich.  

I only have sibilance issues on a small handful of records. Sounds like groove damage.