Draw a square and set filling to Gradient.
Chose gradient type "radial" and set center to 0% for x and for y.
Set border to 0%.
Set "From" to "light blue"
Set "To" to "yellow".
Save.

When you unpack the file, you can see, that "From" is correctly mapped to start-color and "To" is correctly mapped to "End" color.

ODF 1.2 specifies in section "19.218.2 <draw:gradient>":
"radial: defines a gradient where the colors are blend along the radius from the center of a circle as defined with the draw:cx and draw:cy attributes. The outside of the circle is filled with the end color."

So the gradient should start in the center of the circle with blue and blend to yellow. The parts outside the circle should be yellow. But AOO has a yellow center and blue outside of the circle.