Here is why /isearch causes FF14 to hard crash

Date & Time: Anytime
Frequency: Everytime
World name: Gilgamesh
Character name: Luna Sol

I bought 3 new items off the market board to put in glamour dresser and item search afterward crashed my game. Deleting ITEMFDR.DAT did prevent /isearch from crashing my game since deleting this will clear local /isearch cache. Restarted game and opened inventory, saddlebag, armoury Chest, armoire, glamour dresser, and 9 out my 10 retainers and did a few /isearch, worked fine. Opened 10th retainer and tried /isearch immediately after and game crashed. Counted up all my items. I am at 3201 items/stacks. I removed 2 items bringnig myself down to 3199. Item search worked fine with this.

My inventory count that crashes with /isearch:
Inventory - 101
Armoury - 269
Soul Crystals - 23
Saddlebag - 137
Armoire - 324
Dresser - 653
R01 - 175
R02 - 167
R03 - 175
R04 - 175
R05 - 170
R06 - 175
R07 - 166
R08 - 173
R09 - 158
R10 - 160
------------------
Total: 3201 items

Exchanged 2 gear items for GC seals bringing my total item count down to 3199, no /isearch crash with this.
Split a crafting material into 2 stack, bringing total item count to 3200 itesm, game crashes
Re-combinied crafting material into 1 slot, bringing item count to 3199 game, no /isearch crash
Split different crafting item into 2 slots, bringing item count back to 3200, game crashes
Re-opened game and recombined previous split and /isearch is not crashing me



TL;DR: Game crashes with item search if you have 3200 or more inventory slots filled (this count includes 324 armoire items, 23 soul crystals, and multiple stacks of the same item). You are safe if you have less than 3200 items.