Catalysts: Do they actually increase anything currently?

I am confused about catalysts. Are they working currently? Is the number of the corresponding mod value supposed to change on the ring or does it just change it internally? I have used it on this ring and I don't see a change in my current resist at all when I put it on, same value.

catalysts ARE working. the number on the item itself will increase with enough quality, just like quality does to armor and weapons.

your item has 2% increased resistances. 2% of 48 fire iiiis.... slightly less than 1. that's how much impact your quality is having.

and depending how the game rounds, that 'slightly less than 1' fire resist your quality is giving you could be 0 (rounding down to a whole number)