"Fake" Calculated Column

Hi everyone, 

Today I retook an old file that I started working with few months ago and I've discovered something really strange:

In one of the tables, I had created several calculated columns but non of them were currently showing as calculated columns but as regular columns with no calculations at all:

("Test" is just a new one I created to compare)

The thing is that although not showing as calculated columns, they are still working as such: I inserted new data and those columns generated their own values. 

However, when I click them, no formulas apear on top and I would like to apply some changes to them.

Aside from deleting and creating them all over again, do you have any idea of why this could be happening and how to solve it?

Thank you all and sorry for any lenguage mistakes ( I'm not a native speaker)!