Problem

If you star with this path in the curve editor:

M0, 100 C26, 100 30, 0 30, 0 C30, 0 37, 50 50, 50 C63, 50 75, 0 75, 0 C75, 0 83, 100 100, 100

save it, and then reload the page, it will be converted to:

M0, 100 C0, 100 30, 0 30, 0 C30, 0 37, 50 50, 50 C63, 50 75, 0 75, 0 C75, 0 83, 100 100, 100

So the first point M0, 100 C26, gets converted to M0, 100 C0

You can work around it by adding an extra point in the beginning, like this:

M0, 100 C0, 100 0, 100 0, 100 C26, 100 30, 0 30, 0 C30, 0 37, 50 50, 50 C63, 50 75, 0 75, 0 C75, 0 83, 100 100, 100 

Not sure it it's related to the curve-editor or how mojs interpret SVG paths. Will need to investigate further.

Use case

If you wanna create a seamless loop you often need to start and end with a curved point.

Reproduction codepen

https://codepen.io/sandstedt/pen/OJWKXmO?editors=1010