Credit union account shows deposit of rent check was reversed. How can this happen?

[Kay March]

My credit union account shows the following entry:: "Withdrawal RT # NOT DEFINED [TENANT'S NAME HERE] 6060, -$1950.00." indicating that the deposit of the tenant's rent check #6060 in the amount of $1950.00 was reversed, resulting in a debit to my account of that amount. This means, in effect, that he has not paid his rent for this month, July 2024.

How can this happen? Has his check simply bounced? He has been a tenant for six years and none of his checks have bounced. I verified the check with his bank before depositing it. This tenant, by the way, is moving out at the end of August. He received his 60 day notice at the end of June and then delivered his rent check on July 1.