EMMs leveraging the Android Management API (AMAPI) are subject to the default policy requirements Google sets. In February 2024 Google adjusted the default, unset behaviour for UsbDataAccess from ALLOW_USB_DATA_TRANSFER to DISALLOW_USB_DATA_TRANSFER. If your policies did not previously explicitly allow USB data transfer, this function will be blocked on your managed devices.
To reverse this, please set USB data transfer explicitly to allow, and redeploy your policies.