THStorage_(newWithDataAndAllocator) assumes the data was allocated by the passed-in allocator. It doesn’t copy the data, it just steals the pointer.
The snippet breaks because data is allocated on the stack but the THLongStorage_free() tries to free it via the allocator (free()).
Instead do something like:
THLongStorage *t1 = THLongStorage_newWithAllocator(3, &THDefaultAllocator, NULL);
THLongStorage_free(t1);

long data[3] = {2, 3, 5};
memcpy(t1->data, data, 3 * sizeof(long));