You learned a lot about her by hearing her pledge of exclusivity and seeing her new SD account.
I would demote her in my mental lineup but still see her. And continue seeking a higher priority SB. And expect her to fade or ghost at some point, maybe soon.
Good advice above...the sugar world is not a world of perfect information -- SDs withhold info, mislead, evade detail or outright lie, and SBs do the same to us. If you had a great time with her, continue the arrangement and take the deceit for what it really is -- just a day-to-day occurrence in the sugar world.
"Exclusivity" in the sugar world is temporary at best -- sooner or later, she was going to start shopping, or meet a potential boyfriend, or move to Nebraska.
"Great dates" are hard to find -- keep seeing her.
I've seen this many times before and it's no big deal to me.
Theory 1: Consider this from the perspective of a 20-ish girl who sees "simp" behavior all over social media. It's easy to see them thinking they can control the arrangement by making promises they think you want to hear. Of course, that strategy will fail in time.
Theory 2: SB's might "rotate" profiles for many reasons, most not related to you. I can see an SB who has a bad experience with a guy; maybe he's abusive, or a stalker or won't accept "no" for an answer. Maybe SHE acted bad and was reported to SA. Maybe she just forgot her password. Or she has 3-5 profiles - perhaps in different locations - and you just didn't notice them.
Sugaring is certainly a game of transparency and trust - but there are still limits. Arrangements come with a mix of honesty and ambiguity. As long as each of you keeps mutually-material promises, external acts and behaviors are not very relevant.
I had an AA 24-year-old SB for what turned out to be a 3-year arrangement. During that time, using one of my alt profiles I could see her profile come and go every 3 to 4 months. I never asked about it and she never mentioned it. Actually, I was kind of happy to see her do that. She had some ambitious needs that required big funding, and once she realized that I was not going to increase her bi-weekly allowance 5x she decided to supplement her income with supplemental dick. As long as she had fresh test results when we did our monthly results-share, all was good.
Add to all this the idea that even a so-called "exclusive arrangement" does not preclude the possibility of her fucking civilian guys and/or a BF, and the term exclusive really is just, IMO, a construct for saying "I don't want to end this anytime soon."
Life is good
The Cat 
