If tenant payments appear to be a different amount than what they owe, even with partial payments turned off, check the following:
Checklist
Confirm partial payments are off at all three levels — company, property, and lease settings. If any level allows partial payments, tenants can pay custom amounts.
Check the auto-pay amount — Auto-pays are set for a specific amount when created. If the tenant set up their auto-pay for the wrong amount, it will charge that amount regardless of the current balance. Have the tenant update or recreate their auto-pay.