Safari opens some pdfs improperly

Hi I'm currently having issues with safari.

When opening some pdfs in a particular website (e.g. from my own university https://imsarchives.nus.edu.sg/oldwww2/events/2018/lang/files/food.pdf),

it will display like the below:

As you can see, it only displays in a very small area, and cannot be adjusted via command + +-.

But when I open other pdfs like the following:

https://web.mit.edu/rsi/www/pdfs/beamer-tutorial.pdf,

it behaves properly.

Thanks for any helpful suggestions.