Apps UI appearing smaller when opening them sometimes?

[Airwalk117]

When i open an app like Facebook or messenger the app like zooms out and all the font and pictures seem so far away. Im using an s9+, and when i close the app and reopen it, it resets it self. Ive posted two pictures. One is zoomed out ), and the other is after i closed the app and it reset itself

 

[B. Diddy]

Welcome to Android Central! Does anything happen if you pinch-to-zoom in or out?