[{"foo":"foo","baz":[{"D":77}]},{"foo":"bar","baz":[{"A":5,"B":15},{"A":13,"B":34,"C":68,},{"A":192,"B":168,"C":1,"D":27}]},{"foo":"baz","baz":[{"A":5,"B":10,"C":15},{"A":13,"D":37,}]}]

db.collection.aggregate([{$match:{$expr:{$anyElementTrue:{$map:{input:"$baz",in:{$eq:["$$this.D",undefined]}}}}}},{$addFields:{baz:{$filter:{input:"$baz",cond:{$eq:["$$this.D",undefined]}}}}}])