that just means there is not a single galio player in plat+ with 50-125 games on him. They have more or less than that.
That's actually really sad...
They won all 9 games that that winrate applies to apparently. Actually it was saying 9% ish and got cut off.
In any case, sample size is almost certainly to blame.
Play him as a Lane counter and you generally win
Seems legit. Galio is really fucking strong, but no one knows how to use/build him. Although, I'd say there's something wrong with the numbers. It would probably be around a 75% winrate, not 100%.