I have never thought the triple spiral design was anything to do with "Rosenthal", and it does appear in many post-Harris-period bits - the bullet bowls and small, slightly triangulated chargers.
But I had sort of assumed the random patterns were. Even though it isn't an official name, it is something useful to call it.
Mark's book describes images of the random blue over yellow pattern as; "produced for Rosenthal", not as Rosenthal per se. The book says that as there are no records at Rosenthal of Germany of any mention of Michael Harris or Mdina, that it never got beyond producing samples.
Pics of some of my "random patterned blue on yellow stuff".
Edited to add.
I should have said all these bits are rather enormous. The "sweetie jars" are the 16-17" ones, with round polished pontil scars, the cylinder is 10.5" tall. The charger is signed by Michael Harris.