Comment 3 for bug 403445

That seems due to a 'Optimized path data' regression: remove the last point in the XML editor and keep 'z' to close the path -> only 4 mid-markers are correctly displayed.

Path optimization was described in an earlier version of the release notes 0.47 as: «Inkscape used to always explicitly write the closing line segment to SVG for closed paths. For example: "M 0,0 L 1,0 L 1,1 L 0,1 L 0,0 z". With the improved SVG path data writing, Inkscape no longer generates this closing line segment, resulting in "M 0,0 L 1,0 L 1,1 L 0,1 z".»

Somehow the fix no longer works…
Related bug #399381 (which I prematurely closed as 'fixed' ;-)