Events with templates but no custom field values don't save custom fields
This is closely related to #553 (closed), but the fix for #553 (closed) doesn't solve this.
In #553 (closed), if you have an event template that DOES specify values for custom fields, they don't get copied to a new event.
In this case, if you have an event template that does NOT specify values for custom fields, then any values you enter for custom fields are ignored.
This is true both with and without PR #14063 so it's not an unreleased regression.