Zinner thinks that a late dating of Mark (following Detering) may justify a new discussion about who precedes who between Mandeans and Christians on John the Baptist.
In the overall situation that confronts us we have the gospels on the one hand which claim John recognized Jesus as messiah (although the evidence is not consistent; John’s question in Luke 7:17ff. and parallels about Jesus after his arrest shows incertitude) and on the other hand the Mandaean texts that portray John the Baptizer as rejecting Jesus as messiah. A Christian scholar will not in a purportedly scholarly journal openly reject the Mandaean version on theological grounds. Instead, the rejection will be made on the basis of the claim that the gospels are “historical” while the Mandaean texts are not, because the gospels are “earlier” than the “late” Mandaean texts. However, even if we accept this reasoning, which really in some cases could just serve the purposes of theology and apologetics, it runs the risk of overlooking the fact that it doesn’t take long at all for legendary accretions to develop. Such can take place rapidly and do not require several years’ passage
https://www.academia.edu/32005295/The_P ... Influences
A hypothesis is that there was an old prophecy about the Son of Man coming under Pilate, which would justify the dating sub Pilato.