I notice a problem with switching the phone to a 4G network after the call finised. After I finised call phone Mi8 lite stays for couple of minutes in 2G or 3G network. I exchanged already SIM card in new one by my provider Telekom SK. All networks 2G/3G/4G+ are full covered with strong signals. What can cause this problem??? It's very inconvenient, special when I'm connected to my laptop. Thank you.