Munchin2000

My Umbreon appears as illegal, when I click on the error icon the program tells me that the evolution is not valid but that doesn't seem to make any sense. If I change it to any other eeveelution, including Espeon and Sylveon, then it's legal. What could be the reasoning behind this? (Note that I caught this legitimately in Go). I've attached the file. 197 ★ - Tamao - 9349D248177E.pa8

So as far as I know, events can pass the nickname legality check as technically it is possible for them to be nicknamed (albeit extremely unlikely). I noticed however that this doesn't apply to the shiny Zacian/Zamazenta/Eternatus events. Even after changing the event nickname flag from fishy to valid, I still got a legality error. Any idea as to why this happens? Thanks in advance.