Can confirm B20 on Mi8Pro Global running Xiaomi.eu 8.10.18.
Bought it in Taiwan, the box did not have band 20 on it but I guess it's because they don't use it there.
Hard to get a screenshot because it prefers B8 on my carrier (Telenor, SE) but saw it jump briefly to B20 earlier today in LTE Discovery. Will upload screenshot when I manage to catch it again