I had 2 felonies to where I got probation, what if a old employer decides to charge me with theft from 1 year ago
Will that violate my probation because it didn't happen while on probation.

... will that violate my probation because it didnt happen while on probation.

The theft happened, but before you went on probation? That wouldn't be a violation.

If your probation was due to the theft, then the case has been adjudicated already. If this is a separate crime that occurred before you were put on probation then no it wouldn't violate.