Wrong path representation of circles, becomes apparent when duplicating/cloning or reopening

Steps to produce minimal file:

• Open Inkscape
• Create an ellipse/circle (not an arc/chord/etc.)
• Set a stroke to something thick and set linecap to square (Fill and Stroke > Stroke Style)
• Artefact may be visible (see below), definitely visible on reopen.

Steps to reproduce:

• Open specified Inkscape file.
• Change to outline mode (Ctrl+5)
• Select a circle of the template shapes.
• Assign it a stroke. -- (Or select a circle with stroke)
• Duplicate it (Ctrl+D)

What happened?

A little rectangle corrupts the stroke/shape in the circle close node.

What should have happened?

Just duplicate it without any modification.

Notes

• I can solve it selecting all the duplicates affected with the Select and transform objects tool. Next select Create circles, ellipses and arcs tool and finally add a number to any of start/end entries so click on Make the shape a whole ellipse, not arc or segment.
• This does not occurs with new ellipses (into or out the file). Just with the ellipses in the file attached.
• Stroke to path does not solve the situation, but Object to path shows that the nodes are separated.

I would add that when "solving" as I mentioned above, this does not occurs.

Inkscape Version and Operating System:

• Inkscape Version: 1.0beta1 (58d3a45b, 2019-10-02) (Snap version)
• Operating System: Debian 10

Example file.