inkscape gradient square and cookie cutter

I don't know if there may be a bug involved or not. I wasn't aware of that! But it will be helpful to know that now, because instead of changing the Inkscape Prefs setting, which is more or less global, if I have just 1 instance where I need a gradient def not to be shared, I could just copy and paste instead of duplicating. That's an interesting discovery you made about Duplicate vs Copy/Paste. So now, I make a choice before I start a new image, depending on the image. But more recently, I've found that it can be helpful, in certain images, to allow the sharing. (Maybe that's where it is in the dev version, Idk.) I used to keep mine permanently not shared. But in some fairly recent version, developers gave us the choice (although I don't know why it's under Inkscape Prefs > Misc, instead of Inkscape Prefs > Gradients ). When I first started using Inkscape, gradient defs where shared by default, with no choice otherwise. Otoh, as you discovered, it can cause objects color to be changed inadvertently, which can be quite annoying. As Lazur points out, sharing gradient definition can help keep file sizes low. There are advantages and disadvantages either way, depending on your particular needs. So you can check that box, and then whenever you duplicate an object with a gradient, the duplicate gets a different gradient, which won't change when you edit the gradient on the original object. In Inkscape Preferences > Misc, there's a setting 'Prevent sharing of gradient definitions'.

Inkscape gradient square and cookie cutter