Hi.
I am having the exact same issue in SEMrush – “structured data items are invalid”.
It is saying the structured data type is “Breadcrumbs” and the affected fields are as follows:
Field: item.name or name
Issue description: A value for the item.name or name field is required for a nested ListItem.
SEMrush is listing these as Errors (I have over 1,400), so it considers them pretty important.