Roughen path effect corrupted on various actions

Summary:

Okay, Inkscape, looking good, got that path effect looking great. Tweaked those parameters just perfect. Now I'll just take a big sip of coffee and copy and paste that effect onto the other eye...

Steps to reproduce:

minimal reproduction:

• open Inkscape
• open path effects with ctrl+& and then dock it
• draw a circle
• add roughen effect
• uncheck "fixed displacement"
• press ctrl+d to duplicate

longer reproduction:

• open Inkscape
• draw a circle with a black outline and a white fill, about 70mm diameter
• duplicate it side-by-side by dragging and pressing space
• open path effects with ctrl+&
• add a roughen effect to the left circle
• set
  • method = max segment size
  • max segment size = 3.0
  • max number of segments = 2
  • jitter displacement in x = 1.0
  • jitter displacement in y = 1.0
  • global randomise = 1.0
  • handles = along nodes
  • shift nodes = true
  • fixed displacement = false
  • spray tool friendly = true
• click on the main window and copy the left (roughened) circle with ctrl+c
• click on the right circle
• paste the path effect with &
• click on the left circle

What happened?

• the right circle has different roughen parameters from the left circle did
  • method = by number of segments
  • fixed in 1.0.1, by 4fa58e65
• the left circle's roughen parameters changed when it was clicked in the last step
  • max segment size = 0.631
  • jitter displacement in x = 0.63
  • jitter displacement in y = 0.63
  • fixed displacement = true

What should have happened?

• after pasting the path effect, the right circle should have had the same roughen parameters as the left did (fixed in 1.0.1, by 4fa58e65)
• after selected the left circle again, its roughen parameters should remain unchanged

Other notes

I'm not sure if it reproduces identically each time, but it definitely reproduces pretty easily. It seems to corrupt the undo stack as well. I am fairly sure I've seen it corrupt the path effect state without using paste path effect, but it's the easiest and more reliable way I've noticed that does it.

Version Info:

- Inkscape Versions:
  - 1.0.1 (3bc2e813f5, 2020-09-07)
  - 1.0 (4035a4fb49, 2020-05-01)
- Operating System version: Windows 10