Validation errors when using ListSerializer are returned as a list with non-failing entries empty:

[
{},
{"foo": ["error"]},
{},
{"foo": ["another error"]}
]

When using ListField the same information is unexpectedly returned as a dictionary:

{
"1": {"foo": ["error"]},
"3": {"foo": ["another error"]}
}

The current ListField error handling was implemented in #5655 along with DictField, which explains this behavior but I think it would be more obvious for ListField to behave like ListSerializer and return a list instead.