Timelapse Laggy Video

I just bought an iPhone 15 plus less than a week ago and noticed that whenever I take a timelapse video, it lags (and i mean LAGS). It's fine for a little bit when I am holding the phone, but whenever I put it against something to film, it starts lagging like crazy. Like a freeze-frame or something similar. Unsure what to do about this, I have never dropped this phone since it is new, plus I read that other people have had similar issues even with older iPhones as well.

Someone messaged holding it down until the yellow box appears and that seemed to fix the problem, but I wanna know why it is happening in the first place. Should I reset the phone or stop by Apple to get this fixed?