When an iOS BLE peripheral enters the background state, the advertising packets are not emitted in the regular manner and they are placed in a special “overflow” area which is o
With "overflow" area I guess they mean Scan Response Data. To get that data, a device must perform an active scan, rather than a passive scan. In an active scan, the scanner sends a scan request packet immediately after it detects an advertisement packet. The advertising device will only broadcast the scan response data if it detected a scan request.
Android devices only perform active scans, so you should be fine.
EDIT: the answer above is not correct. See http://www.davidgyoungtech.com/2020/05/07/hacking-the-overflow-area for correct information.