Huge and blurry icon in the preferences when using display scaling

When using display scaling, going into preferences shows a very big icon on the button Run Audio Mixer. This is not an issue when using display scale 1, only when using a scale that is bigger than 1.

Tested on x11 and wayland, using adwaita-xfce icon theme. Does not occur with icon themes like Papirus and elementary-xfce.

Screenshot:

xfce4-pulseaudio-plugin 0.5.1, openSUSE tumbleweed