Font size too small for only one user and only some section

I have a user where only in titles, the font size is ridiculy small. It only happens with that user and in Form Titles. 

This is nothing related with display scaling on high DPI screens and RDP. 

There was a post related: https://community.dynamics.com/ax/f/microsoft-dynamics-ax-forum/189862/font-size-shows-very-large-for-1-user-in-ax?pifragment-96834=2#responses

but had no solution. 

Another example