There is a long Post from the incredible "Leolaia" from years ago, you need a bit of time to read it if you search for it, but she proves that they ALWAYS get the wrong day !
Of course, the Gospels contradict each other as to which day Jesus did the "Last Supper" as well, to complicate things, but what a load of fuss the org. makes about NOT really celebrating Christs death ! Farcical !
Other old Threads have shown that even the Passover celebrated by Jews is dodgy as to provenance, there was no Exodus, and Passover "replaced" a former Pagan festival !