Summoners War: Chronicles

So here is a thing that happens.
If you get 1 Million of an item you will learn its capped at 999999.
That is no problem.

The problem is having 1 Million Magical rune pieces stopping you from entering expeditions as they think the craft items are not fitting in the bag.
They are wrong though.
As i can still collect things like iron, yet trying to enter expedition will say i cant with a full bag due to no space for a flame heart for example.
Even though i only am capped on magical rune pieces.
Goes from far to worse when it also does not let me open magical essence boxes, or cooking boxes, or any other box really as the bag is counted as full.

Now sure i can just sell 1 magical rune piece, but this is just 1 item stacked.
The moment people start truly hoarding stuff like me you run into these all the time making you nearly unable to get other items needed to get rid of them.
The game forces you pretty much to either sell them, or use them in alteration.
Magical rune pieces cant even be used in alteration, so there is that.

And selling them is kinda silly when i need them for other things.
As you seen in gallery as well, it also comes with the side effect of drops just being there on the ground.
Wich in terms causes more stress on the server by a ton if alot of people start doing that.

My advice is to do the same as you did with the 999 pickaxes.
And just make them unavailable as soon you max them.
No different drop rates, just they wont appear if the player killing the mob has a full inventory.
And much like the pickaxe, just dont have it say its maxed, but it just refuses to go higher then 999.
Or 999,999 in the rune pieces case.
Either that or consider making the majority of these items that come in bulk into yet another currency.
After all we reach 10m+ gold very easily and even sky cubes had the same issue in the past when i reached past 1m of them.

But its all up to you, just note: 
With 1 max stack item you cant enter expedition or open any boxes.
But you can still enter raid and collect other materials just fine as you leave a trail of unwanted items in your wake.
(Hence why i had so many pieces in that gallery shot to begin with.
Made sense to me to use them as B-day candles instead.)

Have a nice day.