Im always confused with the max speed. Speed chart peaks are 50-70% higher than max speed value in Statistics. For example, statistics of my cross-country skiing shows 40km/h max speed, but the chart has speed peaks up to 70km/h. Statistics values seem to be more reliable.
I have the similar issue. “Statistic” tab says that max speed is 9.15. But “Split time” tab says 12.18 (seems to be more credible). And such misbehaviour is usual. I could attach screenshots if needed.
I’m constantly working on it. There should be some improvements in 2.3 app version.