The latest version of the game that came out this feb, has lots of new changes done to the game but most noticeable are the tweaks for ghost departments, offline drops, and resolve system.

As seen in the image above, we can resolve equipments worry-free because stone ingredients now stacks! I used to lock equipments before so that I can prepare them for future requirements, not fun.
But not all changes are good, I personally prefer that some things should have been left as they are, like how we obtain runes, now only way is thru dungeoning and buying them in gold/gem exchange shop. Even still, those are understandable changes that our devs might have thought out thru for the betterment of the game's difficulties because to be able to maxed out runes is a real deal challenge now. I wish they had lessen the offline drop rate of runes, that would have been more sincere for long time players, rather than this absolute no drop that they did. Nonetheless, I can still say that I'm amenable to sudden changes, what I don't want is what the devs did to our Max Stone...

With that, our chance to maxed out random attributes is strangely identical to Refresh Stone's function, I already wasted 7 max stones for 1 attribute yet still no luck in maxing it.
I get why the need to add some difficulties to the game's features because doing so can reinvigorates the game's experience as a whole, but as I said in the beginning, some things should be left unchanged.
There is not enough money anyway, so now you have to buy stones from the store ...
It's terrible that they removed their drop completely.
There are some bugs with max stones. Judging by the description, it should give a value between the current and the maximum. But as you correctly noted, it began to work like Refresh Stone's
Chance to refresh random attribute's value from current value to max value is the main function of Refresh Stone, even before the February Update. I'm not sure if they dumbed down Refresh Stone too and if it is now functioning less than it was intended before just to highlight max stone's new function because it is not mentioned in the latest change log IIRC.
Refresh Stone Refresh the value of a random attribute you pick from the equipment when you place the stone as material in forging PATCH NOTE: 1.1.035 Modified the function of the Max Stone to refresh randomly between the current value and the maximum value of the selected random attribute. If you look at the description of Max Stone, then every time he should increase the value of the attribute between the current and maximum value. But when I tried to use it, it didn't work. Attribute value remains the same