weird underline and strikethrough

Hi everyone,

I’m having a strange issue in my document. There’s a weird underline (on the 2nd line) and a strikethrough (on the 10th line) that I can’t get rid of (you can see below).

I don’t think they’re part of the text or any character style, because:

• When I type new letters, the text flows normally, but the lines stay fixed in place.

• When I copy and paste the text into another text box, the lines disappear in the new one.

• When I change the color of the text, the lines remain gray.

However:

• When I delete the text box and reflow the text into a new one, the lines appear again.

So it doesn’t seem to be part of the text box either.
I’m completely confused — does anyone have any idea what could be causing this?

Thanks in advance!