ComboBox Misbehaving When we give the id for PopUp

[Lakshminarayana]

I created a Custom ComboBox as below
ComboBox {
id: control
...
popup: PopUp {
id: somename
...
}
}

from Custom ComboBox, again i created one more ColorComboBox.
in this ColorComboBox, i given the contentItem as GridView to show the items in grid view. When i hover the mouse on items, they are vanishing. But when i remove the id property in Custom ComboBox, it is working fine. I'm not understanding reason behind this. Can any one please help me to understand this.

Note: The issue happening in only Qt 5.15.0