Just as an update, I lost my battle to receive the full 50k for 1k spend, and ended up with 25k.
I has sent them a screenshot clearly showing it, and multiple SM's as well. I finally called them, and the guy pointed out that I had just received 50k for a Plat (my MB, part of my 2bm of Plat cards). I explained to him that it was a diff Plat card, and he told me that I can only receive the bonus once for Plat cards, even if one is regular, and one is MB.
I decided to not push the argument since I didn't want him to see that I had just canceled my Biz Plat and MB Plat, and raise any more flags. I also needed to cancel within the 60 day period, and was coming to the end. I thanked him profusely for his help, hung up, sent them an SM, and canceled the card.
Ah well, you win some and you lose some. Maybe I'll churn them both again in a month...