Don't buy UAG's METROPOLIS SERIES IPAD AIR 10.9" (4TH GEN, 2020) casing!
Update (5 November 2020) Day after I contacted UAG customer support, they attended to my request and aware of the issue now. They explained the incident was due to the model has run out of stock (I wonder how wise is that to decide to ship out a flawed one at the first place). They promised to send a replacement to me once it's back in stock.