Can BF definitively answer this question? No.

Is something fishy? Yes.

If you have a spare several hours, go down the rabbit hole that is the Marathon Investigation website. It's truly fascinating stuff the lengths people will go to cheat at marathons, and ultras. There's usually some patterns, too, most commonly course cutting and bib mules.

Since you said there are pictures of her wearing the timing chip, but also no times that were registered, my guess would be course cutting. Timing errors do happen (and Marathon Investigation has also exonerated people wrongly accused of course cutting) but it's pretty uncommon. Usually when there is no time data recorded combined with "thou doth protest too much" it means someone cut the course.

Motivation? Who knows. You said she needed the time to qualify for another event. Did she end up qualifying for that other event? If so, there's your probable answer.