Peter I don't know why I didn't think of this before, but there is another player I saw recently with a "RC" designated card in 2017 product and 2018:
2018 Paul DeJong
2017 Paul DeJong (this isn't his only 2017 RC, but used to illustrate the point)
I do believe the 2018 silver pack may be an error, as his other 2018 cards don't have the RC logo, but still relevant to what you were pointing out earlier.