Could having the reference to 'List' be messing things up for you? (See red text in formula below):
Formula: copy to clipboard 
{=INDEX(Table2[DATE],MATCH(MIN(IF(ISBLANK(Table2[DATE])+COUNTIF(B$67:$B67,Table2[DATE]),"",IF(ISNUMBER(Table2[DATE]),COUNTIF(Table2[DATE],"<"&Table2[DATE]),COUNTIF(Table2[DATE],"<"&Table2[DATE])+SUM(IF(ISNUMBER(Table2[DATE]),1,0))+1))),IF(ISBLANK(Table2[DATE])+COUNTIF(B$67:$B67,List),"",IF(ISNUMBER(Table2[DATE]),COUNTIF(Table2[DATE],"<"&Table2[DATE]),COUNTIF(Table2[DATE],"<"&Table2[DATE])+SUM(IF(ISNUMBER(Table2[DATE]),1,0))+1)),0))}
-Moo