Landlord saying his lender has requested tax returns of tenants

We are renters and have lived at this property for approximately 2 years. Today our landlord reached out saying his lender is requesting copies of my husband and I’s tax returns from 2018-2022. He said they are requesting this because his loan payments are income based and he recently disclosed on the phone, but not yet on paper, that he is renting the property, so they requested this additional documentation for their files. This seems really strange and unnecessary.

Our incomes do not apply or affect his income in any way. We meet the income requirements he set for renting the property. I feel the only info that should concern the bank is the date we started renting, our monthly rent payment, and verifying through our landlord’s bank statement that the payments are there. Is there something I’m missing here? Why would a bank need access to the tenant’s financial history? Our finances are obviously completely separate from our landlord’s.