FXML binding expression error (false positive)

Intellij IDEA - 2020.1

OpenJFX - 14.0.1

My FXML code is:

<?import javafx.scene.control.Button?>
<?import javafx.scene.layout.GridPane?>
<GridPane fx:id="gridPane" fx:controller="sample.Controller"
xmlns:fx="http://javafx.com/fxml" alignment="center" hgap="10" vgap="10">
<Button text="test" prefWidth="${gridPane.width*0.3}"/>
</GridPane>

the issue is in that line:

<Button text="test" prefWidth="${gridPane.width*0.3}"/>

Cannot resolve symbol 'width*0'

The project and the binding works fine.

I've uploaded the project via web form (https://imgur.com/a/kTBrJNN)