Inline error message doesn't show up in VSCode-Insiders

HI! I recently moved from VSCode to VSCode-Insiders. I am really enjoying working there, but I cannot see the red inline error message when there is something in my code that is not working. For example, while in VSCode I get something like this

if I run the same code in VSCode-Insiders, I don’t see the red line, which is really inconvenient for debugging, especially when working with multiple files.

Any clue of what could be happening? This is a default feature in VSCode.