This happens quite frequently. Most of the time the court file is correct however due to the fact that it was originally filed as a misdemeanor the case number makes the case look like a misdemeanor. Most courts use case numbers to designate the type of charge so a misdemeanor case has a number that starts with an M, felony cases have a number that starts with an F.
The first thing to do is go to the court where you suffered the conviction and ask to see the minute order for the hearing that you changed your plea to guilty or no contest. Make sure the clerk recorded it as an infraction. If not then put yourself back on calendar and ask that it be corrected. You may need a lawyer to make sure this is done correctly.
What your employer probably saw was your record of arrest. Even though your charge was reduced to an infraction, you were arrested for a misdemeanor and that will show on your record. There isn't anything a lawyer can do about that.
Mr. Martin's suggestion is a good one. BUT get a certified copy of the minute order. Also note on your calendar when one year from the time you entered a plea and arrange for an expungement.
The above is not intended as legal advice. The response does not constitute the creation of an attorney client relationship as this forum does not provide for a confidential communication.
Infractions normally do not show up on record checks. You should probably contact the court to make sure there was no error made at the time of entry. More likely than not, it was entered into the system as a misdemeanor rather than an infraction. You have to ask them to remedy the error. If you have the papers showing it was reduced to an infraction take it to the court's clerk and ask them to change it. If not you can search the record database for it.
Getting an expungement is another option to get rid of misdemeanor.