Not necessarily. This depends entirely on two critical factors: (1) Whether that university utilizes TurnItIn for evaluating college application essays, and (2) exactly what settings they employed regarding retention in the repository (and likewise for the subsequent submission…whether it checks such repositories).
The first is dubious. Although I’m sure many schools do use a plagiarism checker, it’s questionable whether that’s appropriate for an admission essay since you haven’t yet been admitted, they haven’t had the chance to communicate honor and integrity policies, (whether that comes in the form of an academic catalog, policy handbook, code of conduct, or some other similar agreement), and the school doesn’t yet have a standing agreement with you to abide by that. If a school employs plagiarism checking before those are in place, it’s assuming some risk and potential liability…unless they’ve communicated such expectations clearly in the instructions they provide for how that essay is to be submitted and how it will be evaluated.
Regarding the second factor, instructors and TurnItIn administrators always have the option of choosing whether to add submissions to the repository as well as which repositories to utilize or exclude (and it’s for exactly this very reason - you wouldn’t want an assignment in earlier weeks for a first draft added to the repository because then it would show up as a 100% match on the final assignment). But any instructor or college official who has a clue at all about how TurnItIn works will know this and will know how to configure the settings to avoid this problem. And they’ll know that a 100% match is a result of failed settings and likely evidence of an earlier submission in its entirety, and so they will know how to handle that. If a school can’t figure that out, you don’t want to attend that school.
Does it happen? Yes, all the time (and the responses you’ve received so far are indications of that). But when it happens, it’s by people who don’t know what they’re doing, or by instructors who just accept the default settings without actually checking or thinking how their TurnItIn-enabled assignments should be configured.