Firebase Analytics - sending nested object as event log

Hi there, I'm using firebase analytics for my app. The goal I'm trying to achieve is to log several informations about the user, which are located in different DTOs. For example if user clicks `removeProductFromCart` button, I want to log which product that was and this is another DTO, if user clicks `clearCart`, I want to log the list of the objects that were contained in the cart before..
I hope I explained it in an understandable way. So the result must look something like this :
`analytics().logEvent('remove_from_cart', {product: {id: 123, name:"test" ...} userInfo: {id: 123, userName: "test" ...} })`
But when I do following, it seems to be working - since it doesn't give any errors, but it appears as firebase_error 21 in firebase console. Is this approach not supported ? does any other approach exist for achieving the same goal ?
Thanks in advance !