Strange issue in a php file

Hello.

I was checking if I could access to the php files directly in the browser and I saw that one of them shows part of the text or/and code.

I tested this with:

– twentytwenty

– twentyfifteen

– catch-evolution

– blankslate

The code or text displayed is part of that .php file, but not all. I am not sure if this important, if I am allowed to explain this issue here nor where I should report this problem to give more details.