Amdapori Stone - Unlucky or possibly bugged/moved ?

I know this has always been an uncommon drop but I've done literally over 50 solo runs now and Ampdori Stone hasn't spawned out of the relevant chest a single time.

Just RNG unlucky ? I wouldn't normally post this but this number of runs seems high for not a single drop.

Probably just unlucky. Only other thing I could think of is that going in undersized prevents it from dropping but since it's from a chest not a mob/boss drop, it's unlikely.