Debian issue: echo not adding a new line by default

Question

I've had several issues with a new Debian installation, that I've tracked to be caused by the fact that when interact with a file or if it's part of a script echo doesn't add a new line by default, so if I use 2 echo commands that previously made 2 lines in a file (I've used debian in WSL before and there it works perfectly), the second line ends up replacing the first.

It seems to be independent of the terminal. I used the default terminal that came with XCFE desktop, but I had so many issues that I installed kitty instead, which has been much better, but this issue continues, so I don't think it's about the terminal. Echo works normally if I just do a terminal command, so I'm thinking the script or file interaction does something different.

Any idea how to fix this issue?