uint64 zero = 0;
    uint64 nonzero = 0x100000000;
    array<uint64> array_zero = {zero};
    array<uint64> array_nonzero = {nonzero};
    print("" + (zero == nonzero)); //false, good
    print("" + (array_zero == array_nonzero)); //true, but should be false
    print("" + array_nonzero.find(zero)); //0, but should be -1

As far as I know arrays of 64-bit types are okay otherwise, it's just these two contexts that use the internal Equals method that are behaving improperly.

Violet CLM said:

As far as I know arrays of 64-bit types are okay otherwise

Ah, actually, sorting also gets confused:

array<uint64> arr = {0, 2, 4, 0x100000001, 0x100000003, 0x100000005 };
arr.sortAsc();
for (uint i = 0; i < arr.length; ++i)
	print(formatInt(arr[i], "H"));

This prints, in order: 0, 100000001, 2, 100000003, 4, 100000005.