crash on undo of node edit of powermask LPE (set via inverse mask)

Summary:

Inkscape crashes if I hit CTRL-Z to undo moving a node. Crash message:

** (org.inkscape.Inkscape:15049): CRITICAL **: 15:38:21.727: virtual void Inkscape::XML::SimpleNode::changeOrder(Inkscape::XML::Node*, Inkscape::XML::Node*): assertion 'child->parent() == this' failed
**
ERROR:/build/inkscape/src/inkscape/src/xml/simple-node.cpp:497:virtual void Inkscape::XML::SimpleNode::removeChild(Inkscape::XML::Node*): assertion failed: (child->_parent == this)
Bail out! ERROR:/build/inkscape/src/inkscape/src/xml/simple-node.cpp:497:virtual void Inkscape::XML::SimpleNode::removeChild(Inkscape::XML::Node*): assertion failed: (child->_parent == this)

Emergency save activated!...

Steps to reproduce:

• Open the SVG I was working on (arms.svg).
• Move any node in the grey cloud.
• Hit CTRL-Z

What happened?

Inkscape crashed.

What should have happened?

Inkscape shouldn't crash 😁.

Version Info:

- Inkscape Version: Inkscape 1.0.1 (3bc2e813f5, 2020-09-07), Pango version: 1.48.0
- Operating System: Arch GNU/Linux (Linux 5.9.14-arch1-1)