Bug: Note edit Spectrum Hz values seem wrong?

This is with the Grand Blüthner piano.

Suppose you set the scale length to 2.72m, and go to the spectrum note edit view for the note "B3". Then the first harmonic is listed as being 494 Hz, and the 11th is 5700 Hz. This seems correct and is about 83 cents sharp.

However, now let's say you increase the scale length to 10.00m. The 11th harmonic now says it's 5730 Hz, or even sharper at 91 cents sharp. So it is even more inharmonic than at 2.72m. However, string inharmonicity is supposed to *decrease* as string length increases, right? Why is it saying inharmonicity is greater?