set ArcGISMapImageSublayer.opacity error -Change color but not transparent

[SonMinh]

In Android (use Kotlin) set ArcGISMapImageSublayer.opacity=0.5f for sublayer only change color but not transparency (cannot see below layers or basemap) 

But if set for layer ArcGISMapImageLayer.opacity=0.5f it works ok (but we need change transparency of each sublayer)