What is the most appropriate way to address someone being given a false PT score, while minimizing the damage to their career?

NJP.

It's better for her to fess up. You're right in struggling with your conscience. No matter what the consequences for her, you can't put your own integrity at risk--it's priceless. An option might be to approach her and encourage here to confess to her superiors, then offer moral support by accompanying her. Otherwise, you have no choice but to say it like it is. You don't have to offer her an ultimatum, you just have to say this is a discussion in both your best interests.

She needs to come clean and accept the consequences. You are under no ethical obligation to remain silent about an untruth. Would be ideal if could approach her and ask her to fess up on her own as a matter of honor. But up front with her that as a matter of conscious you cannot go along with this false score. You don't have to give her an ultimatum, it only needs to be a discussion. Heck, you could even offer moral support by accompanying her with your superiors.

It’s been a while since I had to worry about a PT test, but it seems to me that this makes the army sounds like it’s turning into a bunch of cheaters. I’m disappointed, but not surprised. They wanted women to be on the same level as men, but noting the physical differences, they have to resort to cheating. I have other ideas as to how she was allowed to pass, but I’ll keep those to myself.

This is falsifying an official record. All I can see is General Discharge under less than Honorable Conditions. I have no mercy for those who will knowingly put a false record entry.

How was it rectified as you commented. She and whoever conspired this should be held accountable for their actions.. so sad that this goes on. I’ve seen it done. After be a scorer and hearing that it was changed by someone higher up

As a Marine her lack of integrity is to me utterly unacceptable. She need to be pulled aside and given the opportunity to come clean on her own or face the music. For you, if she refuses to come clean go 1st to your Sgtmajor and allow the process to work. If you go directly to your xo or co you may piss off the NCOs above you- not advisable LOL

Her actions most likely deprived another Soldier of an important promotion. From the information provided, she appears to have no concern that her actions negatively impacted someone else’s career or enlistment and is only worried about being caught. I would bring this to the attention of the chain of command and lose not one night’s sleep or have a single regret.

It was cheating - same as if they'd studied together. Same as if friends passed test questions to each other. All involved should receive an article 15 or be dishonarably discharged. People have been reduced in rank as well. It's hard to believe that she wasn't aware she was out of shape. So she lied as well.

I can only address this from two viewpoints: one as a retired civilian lawyer and one as an Instructor in a chapter of the Young Marines organization when I was 69 and 70 years of age.
As a lawyer, I'd question how the inquirer knew the test result was falsified. Was it intentionally falsified or was it simply a very lenient tester? Or did she really get the score reported but grew out of shape between tests? From the description, it appears that she knew she didn't earn the score, but how badly was it off?
From the standpoint of being an old Instructor, let me say that I ran with the kids and did PT with them, yelling "If I can do it, YOU can do it!" (And I was wearing "utilities" or BDUs and "boondockers" while they were wearing shorts, t-shirts, and sneakers. Thank God for asprin!) My point is, if you want to be a leader you have to be expected to hurt, bleed, and sacrifice...And be honest about your own capabilities. The word "leadership" is already being so diluted and mixed up with "management" that it is losing its honorable meaning. Just my opinion.