Clearly, something is wrong, the curve should be relatively monotonic decreasing, and the odds should not go up at the right side of the scale. You will have to do some digging to find out what the problem is.
Question: did you fit the model on only loans that were actually booked? This will cause bias in your model and in the odds ratios; but usually this bias shows up in the lower end of the scores, not in the higher end of the scores. There could be other bias in the higher end, although I am not able to specifically state a reason. Another problem could be a very small number of loans with a score above 300, in which case maybe your binning is wrong or needs to be modified.
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Paige Miller