Are there journals that prevent authors from contacting reviewers? This question stems from a comment to a recent question - "instructions for authors at some journal(s) stating that authors should not contact (potential) reviewers". 

I was wondering whether journals do punish authors who reach out to reviewers. Has there has been instances or has anyone heard of punishment or submission rejection when authors approach their reviewers, especially if the reviewers complain or report the interaction to the editor. 

There was a 6 month study of 239 authors that found a 11% accuracy of authors guessing the reviewer of their submission.
The journal is asking that those submitting papers do not contact potential reviewers.  That is very different from not asking you to contact the actual reviewers, although there are norms to be followed in that situation.

I can imagine new authors thinking they need permission from the potential reviewers if it is fine to put them on the list.  After all, that is recommended before you put a name down on a resume as a reference to a job application.  Authors should just put down names of possible referees, without checking if they are available for the assignment.  That is the editors job if they decide to use a name from the author's list.

The study you cite refers to the second situation.  If you have an idea who was the referee on the paper, you can still interact with that person as if they were not the referee.  If you aggressively ask that person if they were the referee, you may regret that action. Recall that revenge is a dish best served cold. That person you angered  might referee another one of your papers in the future.

There is little need for a formal punishment mechanism at a journal, although some journals must surely have one.  Your editor today might be tomorrow the person who is allocating travel funds at an upcoming conference.  The person at the conference asking you to not go overtime today might tomorrow be on the hiring committee where one of your students is trying to get a postdoc.  I doubt you will find many instances of a formal censure.