Justice denied due to a TECHNICALITY? How often does THAT happen? Basing "justice" or lack thereof on a specific set of words said or un?

Prosecutors must follow their agreements.  Case should have never went to court.  

I know many caaes are dismissed for lack of standing or filed at the wrong time.  I know people get off if they were not read their rights etc.
Many speeding tickets are dismissed on technicalities. That is how the lawyer gets them off your record.