That might just mean that all the version between 72 and 78 are Peregrine specific changes. You had a similar thing happen on the Teric new computers come with one firmware, while the release version stayed an older version. They made a new firmware to support a hardware change that only affected new production computers.
But we will see in the coming months if it was a fork or not.
Very possible. Time will tell. At this point the only facts I know for certain are (1) I just got my Peregrine today it came with firmware 78 which is listed as the latest on the SRI website and (2) my Perdix AI latest firmware remains 72.