I dont think is that rare Ive seen seedlings with 3 cotylendons, Some Apple seedlings recently sprouted with 3 (2 in 20 aprox) I also have seen it in Cupressus sempervirens
haha doesnt need to be a joke it perfectly could be something very unusual like a 4 leaf clover or even more rare, but in this case I dont think so as Ive seen it often
I've also had a number of species germinate with 3 cotyledons. I grew some triffid tridents on to see if there was any difference in nodes or budding but the all turned out normal for the species.