On almost all dies for this type the legend reads PONTF MAX up the right hand side and and TVTOR REG down the lefthand side. (The NTF, and arguably also an I, are in ligature.) On this specimen the die cutter and turned this arrangement around. (A variation not noted by Crawford or the sales catalogue.)
The whole of legend describes the Roman figure (M. Aemeilius Lepidus, cos. 187), he is both chief priest and guardian of the king (Ptolemy V = the left figure). However, in the normal layout the legend also serves to clarify and label the image. We see the intentionality of the original legend lay out in this error. Here an uninitiated viewer might mistake the boy-king for the chief priest! Rather than understand that he is the king ruling by the grace of Rome.
Here is another specimen from the same reverse die in even nicer condition. And another much uglier one that is also die linked, an illicit hoard must have come to the market with a batch of coins from this previously unknown die. I hate the thought of the data lost with the dispersal of an undocumented hoard. We could know so much more! This specimen was was catalogued for auction correctly as a legend variation and seems to have been known since 1990 at least.