When using backspace you can see prompt flicker in custom REPL

I'm not sure if this is the right place to ask this. Or should I ask on StackOverflow and show my code. But maybe someone will be able to tell my by just looking at the symptoms. I have a custom REPL in Node.js where I do a lot of stuff to add syntax-highlighting and auto indentation. And recently noticed that when I press backspace, the cursor jump to the beginning of the line where prompt is located and the whole like flicker. This only happens when doing backspace. And it started to happen probably a few months ago. On the gif it looks like the whole prompt disappear, it's very fast not like this, but noticeable. It's not because of a new version of Node, because it works the same on older versions. So something needed to happen to my GNU/Linux system, something got updated and introduced this behavior. I've tested this on Fedora Xfce terminal, on xterm it's not always as bad, the cursor doesn't jump on every backspace, but sometimes it does. Any tips what I should look at and maybe where to report this if it's a bug, would be great. Also, maybe someone can explain what is happening and if this is not a bug. **EDIT** I've noticed that the same happen with Fedora 41 dnf install when it display multiple progress bars, everything flickers during animation. I want to report this a bug, but I need help, where I should report this? Should I write issue with Fedora or find the upstream project?