Conversion to knot or mph from m/s fails

[c3d]

Seen in the demo for 0.7.8, around 14:15 in the video.

[c3d]

Cannot easily reproduce, either on simulator or hardware.

[mahi2003]

I had the same issue, so it's definitely not a rare occurrence. However, after resetting the calculator I am unable to reproduce. Resetting the calculator also fixed #988 for me.

[c3d]

I suspect this is another case where I leave the units file open (DMCP has this constraints that you can only open one file at a time).

Let's see if we ever see it again. If you do, @mahi2003, please notify me.