[{"cast":["First Actor","Second Actor"],"directors":["First Director","Second Director"]},{"cast":["Actor Director","First Actor"],"directors":["Actor Director","Firt Director"]},{"cast":["Actor Director","First Actor"],"directors":["Actress Director","First Actor"]},]

db.collection.aggregate([{$addFields:{directors:{$cond:{if:{$isArray:"$directors"},then:"$directors",else:[]}},cast:{$cond:{if:{$isArray:"$cast"},then:"$cast",else:[]}}}},{$match:{$expr:{$gt:[{$size:{$setIntersection:["$cast","$directors"]}},0]}}},{$count:"have_common_value"}])