When using a multi-valued date field (_mdt) Solr views will not render any values that get returned as the date field handler expects a singular string to be rendered not an array.
Steps to Reproduce-
Create a Solr view
Configure a _mdt field that has multiple values in the Solr index
Render the view
Note that there is no values present
With a view with a _mdt field the date format is applied to all values present in the field and is spaced with commas.