Is it considered disbelief for one to see a piece of paper containing Quranic verses on the ground where people walk and leave it, without intending insult or mockery? And what is the most authoritative opinion on this matter?

The Maliki school of thought stipulates that whoever finds a paper containing the remembrance of Allah or His Messenger and intentionally leaves it, despite being able to pick it up, commits an act of disbelief (kufr). Others, however, are of the opinion that such an act of disbelief is contingent upon there being a deliberate act of disrespect towards it.