A ridiculous result of shap_decision_plot in logit link and how to explain it

[Aurora425]

I'd like to draw a shap decision plot to Identify typical prediction paths (say, plot all of the predictions in the probability interval [0.98, 1.0]) , but sadly I've got a plot that all the results point to the middle of the top bar rather than to the right end as the attached file. My code has no problem since the other target does well in this target. Btw, I've tried all kinds of interval including a random 100 samples, but they all point to the middle once I choose the logit link. I‘m wondering how to explain this result.