Created attachment 148650 [details]
with shape path "M 0 0 5 10 10 0 N"
According to ODF 1.2 section 19.145 the command M has the special rule, " If a moveto is followed by multiple pairs of coordinates, they are treated as lineto."
Therefore a path like e.g. "M 0 0 5 10 10 0 N" should be treated as "M 0 0 L 5 10 10 0 N".
The attached file should show a line from top-left to bottom-middle, then to top-right. But the file has only an empty shape. You can use Calligra Karbon to see, how the shape should be rendered.
I will solve it so, that on opening such shape, the command L will be inserted. When saving, the command L will be present, so that older versions of LibreOffice can then render the shape correctly too.
Fixed with https://gerrit.libreoffice.org/#/c/66888/, commit id=76c7a6c39d769cb9bdb9b951d9f95507c0139372