^^ But that's normal
@SorrySkater, because figure skating is a difficult sport and things are always changing; skaters are always working on improving. It takes time. Serafini/Tran are so new, I really wouldn't get down on them, or use this outing as a measure of their abilities. Clearly, their jump timing and abilities together in that respect seem good. It's normal to only be able to compete a 2-twist until time, trust and skill allow Olivia to do a 3-twist. In Mervin, Olivia has a good partner with whom she can grow and learn from. She is new to pairs, don't forget, so it will take time for her to get elements like death spiral, throws, lifts and 3-twist together and working on all cylinders. And Mervin, judging by his recent comments, feels his partner is a saint.

That bodes well for them, if they remain healthy and stick together and maintain competitive desire.
Practically all U.S. teams on this senior roster look good to me (quite a few look great and/or exceedingly promising). They were certainly all very enjoyable to watch (aside from Alexa/Chris' troubles and Olivia/Mervin's newbie snafus), unless you are a naysayer and a spoilsport, or just not into pairs skating.
ETA: By 'you,' I don't mean I'm singling you out in particular. Sorry. I think in following skaters, it's the measure of a true fan though to be able to stick with them when they are down and out; to help encourage and support them and to root for them. It's easy to get on bandwagons when things are going well. But things don't always go well for athletes every time out. It's a journey, and figure skating is the most difficult athletic journey of all, from what I've seen.
My heart goes out to Ashley and to all who are coping with tragic loss:
https://www.instagram.com/p/Bs3vRiWFDHU/ Thanks to Ashley for sharing her memories
And kudos to all the U.S. pairs teams who performed so well yesterday!