Not sure if I am right or if this change is already done for 4.8 or 4.9, but consumable IAP bool doesn’t work as intended yet. Line 163 in OnlineStoreInterfaceGooglePlay.
bCreatedNewTransaction = AndroidThunkCpp_Iap_BeginPurchase(ProductRequest.ProductIdentifier, ProductRequest.bIsConsumable); // TPMB - update begin purchase to use a consumable flag.