Resume Mismatch against reported OPT employer

Hi all, I did both my undergrad (+ non STEM OPT) and graduate studies in the states. I am on my initial OPT (STEM eligible) and my employer is going to file for my H1B.

When I applied for my current position, I had listed a company X in my resume (position was stated as trainee) where I was doing a training program. However, this was not reported in my initial undergraduate OPT as I had reported employment with another company Y. I did not state that company Y in my resume as it has since dissolved and I thought that if any references were needed, I would not be able to provide it. During the training program at X, I did not sign any contract nor received any payment.

  1. Would this be considered unreported employment during OPT? if yes, what would be the implication of it?
  2. Any idea if this will impact my H1B application?
  3. Should I update my resume to include the actual company that was reported during my previous OPT?

My lawyer in current company suggested to call my previous Uni to report the training program but I am hesitant on that approach. Any help will be greatly appreciated!