There could be an issue whereby some attacker controls the hash inputs which happen to be integers, and chooses a sequence which collides to the same hash value

There could be an issue whereby some attacker controls the hash inputs which happen to be integers, and chooses a sequence which collides to the same hash value. It would be easy to identify such a sequence. It just doesn't seem to have been identified as a real isssue, probably because the most commonly hashed external data is character strings. (For those, there are countermeasures like a properly scrambled hashing function, modified by a seed that can be randomized.)