My son received two years probation in January of this year on a second degree assault charge in Baltimore County, Md. He recently (May 2nd) received a probation before judgement in Worcester County, Md. Is he in violation of his probation?

Yes.

Was there a new crime that he did after Jan when he was put on probation ?

Or was the new second probation, a result of a crime that happened before he was put on probation.

If he did a crime in Nov of last year, but it did not come to court till May of this year and got probation, then it would not, since it was not a new charge
** but his PO should have been informed of the old out standing crime and the new court dates