Bug: Mesh option in Heightfield produces no result

The mesh option in the Heightfield command produces no results in Rhino 7 SR 10 (7.10.21256.17001, 2021-09-13). See the screencast below:

The file I used was this one:

Hello - set the samples to match the image - 1130 by 794 and ask for a vertex at each sample, in the dialog-



Weird, it’s working in a new file now. Thanks!
E: I suspect it was a scaling & snapping issue with the tool when inputting the length.