dis-turb (di-sturb') tr.v. 
dis-turbed, dis-turb-ing, dis-turbs.
1. To break up or destroy the tranquillity 
   or settled state of.
2. To trouble emotionally or mentally; upset.
3.a. To interfere with; interrupt. 
  b. To intrude on; inconvenience.
4. To put out of order; disarrange.
 -dis-turb'er n. -dis-turb'ing-ly adv.

A disturbance is caused when these replicants appear and Deckard is forced to "retire" them.

Deckard has never reitred a human by mistake.

Deckard has never met a NEXUS 6 replicant.