Yesterday I had an awkward encounter with a colleague. I just greeted him as I passed by him in the hallway and in return he accused me of not wanting to fix my algorithm for a report I have developed for their department. I told him I wasn't made aware of any bug and he accused me of putting the blame on them for not knowing what they needed. He left visibly angry at me and told me "It's fine don't fix it" in a very irritated tone.
I honestly have no clue at all what he was referring to. His coworker even commended me last month for my work.
Now my question: how do I defuse this situation? Obviously, if something is wrong with the report then I want to fix it but I'm not sure how to approach this. I feel contacting him only might not work so well as he's angry at me and will only lead to confrontation. I thought about contacting his boss but that may only aggravate the situation as he might think that I'm trying to make him look bad to his boss.