How to define background color to sprite in PlantUML's legend?

Question

The code at the bottom generates the output below. How can I set the sprite's background color (white) to the background color (purple)?

@startuml Archimate

skinparam defaultTextAlignment center
skinparam backgroundColor #EEEBDC

skinparam Legend {
    BackgroundColor #EEEBDC
    FontColor #000000
    BorderThickness 0
}

!define ICONURL https://raw.githubusercontent.com/tupadr3/plantuml-icon-font-sprites/v2.2.0
!include ICONURL/common.puml
!include ICONURL/devicons2/docker.puml

skinparam componentStyle rectangle
skinparam ArrowColor #546E7A

!define _dockerbackgroundcolor #7B1FA2
!define _dockercolor #CE93D8
!define _dockercoloralternate #F48FB1
!define _dockertextcolor #FFFFFF

DEV2_DOCKER(app1,<color:_dockertextcolor>FileMonitor,component,_dockercolor) _dockerbackgroundcolor
DEV2_DOCKER(app2,<color:_dockertextcolor>DataAPI,component,_dockercoloralternate) _dockerbackgroundcolor

app1 -down-> app2

legend right
|<_dockerbackgroundcolor><color:_dockercolor><$docker>    | App1 |
|<_dockerbackgroundcolor><color:_dockercoloralternate><$docker> | App2 |
endlegend

@enduml

Answer 1

According to here it was a bug.