Faced the similar issue.I also solved it by turning off the debug mode.In my case it was pos in odoo 18.

Dear @OdooNomad
what do you mean by props? and where can I find it,
please can you guide me on where and how to put your code to solve this issue permanently?

I faced a similar issue before. The error message I encountered was:

Uncaught Promise > Invalid props for component 'ExistingOrdersDialog': unknown key 'title', unknown key 'orders'

This error only appeared in DEBUG mode. However, I managed to resolve it by adding the necessary props to the component as follows:

export class ExistingOrdersDialog extends Component {

    static components = { Dialog };

    static props = {

        close: Function,

        onAddOrder: Function,

        onSaveOrder: Function,

        title: String,

        orders: Object

    };

}

After including these props, I restarted Odoo and reloaded the page to ensure the new assets were loaded, and the error disappeared. In your case, I recommend checking if the 'currency' prop is defined in the TaxGroupComponent. If not, define it as a String type.

Best regards

Hello, you need to enable currency defined on purchase order. Go to currencies menu and check if all currencies used on purchase orders are active.

Hope this helps.

BR

I have been able to observe simillar problem recently on SH. And what have been able to identify is that will happen when I start to pickup products without set Client at first. 

Behavior is strange and should be handled without error as values should not be computed until Client is pickedup...