BLE ANDROID bad what happens?

Only BLE IOS works very well, BLE ANDROID is always bad why?
Some time ago, BLE ANDROID very often did not finish the “SCAN”, but when it ended the “SCAN” it was fine, now, the “SCAN” ends it correctly but often, during use it disconnects, if I enter the commands very slowly it works but if I work normally “BLE ANDROID” disconnects. I am tired, “BLE” is very important in my apps. Can anyone tell me what happens?