rma/rma_sale_mrp/views/rma_views.xml

<?xml version="1.0" encoding="utf-8" ?>
<odoo>
    <record id="rma_view_form" model="ir.ui.view">
        <field name="inherit_id" ref="rma_sale.rma_view_form" />
        <field name="model">rma</field>
        <field name="arch" type="xml">
            <field name="product_id" position="before">
                <field
                    name="phantom_bom_product"
                    attrs="{'invisible': [('phantom_bom_product', '=', False)]}"
                />
            </field>
        </field>
    </record>
    <record id="rma_view_tree" model="ir.ui.view">
        <field name="inherit_id" ref="rma.rma_view_tree" />
        <field name="model">rma</field>
        <field name="arch" type="xml">
            <field name="product_uom" position="after">
                <field name="phantom_bom_product" />
            </field>
        </field>
    </record>
</odoo>