I see you added a method to bypass the list throttling occurring in SP 2010 and 2013 when exceeding 5000 items in a list for CASCADING DROPDOWN LISTS, however, I am experiencing this same issue when the child list used in vLookup exceeds 5000. It stops returning results. Is there a workaround?
To set up the relationship, the child list does a lookup (lookup field called EA Request ID) to a single line of text field in the parent (SLOT called EA Request ID). When the child list exceeds 5000, the parent form stops pulling in the children and throws an error.