Unfortunately delayed reaction

The collar does what it should, sprayed when the dog barks, but unfortunately delayed, so the question is whether the dog really still understand why the thing sprayed on his neck.
It also sprayed sometimes for no apparent reason, for example if the dog lies down, paw licking, climbing stairs or doing other movements associated with no loud noises.

A friend of mine has bought such a collar 100, which is much more reliable and precise than this. I wish I had not seen here on the money.