p.clj

(filter
  identity
  (map
   (fn [[previous current]]
     (let [previous-items (:items (last previous))
           current-items (:items (last current))
           previous-v (apply max previous-items)
           current-great-previous (filter #(< % previous-v) current-items)]
       (not (empty? current-great-previous))))
   (partition 2 2 {} {"1" {:items [1 2 3]} "2" {:items [-1]} "3" {:items [2]}})))

t.clj

(filter
  (fn [[k v]] (:invalid v))
  (reduce-kv
   (fn [previous current-k current-v]
     (let [{current-items :items} current-v
           previous-items (:items (last (vals previous)))
           current-great-previous (filter #(some (fn [v] (> v %)) previous-items) current-items)]
       (if (not (empty? current-great-previous))
         (assoc previous current-k (assoc current-v :invalid true))
         (assoc previous current-k current-v))))
   {}
   {"1" {:items [1 2 3]} "2" {:items [-1]} "3" {:items [2]}}))