This also happens with Feliz Cumpleanos. In Chabacano, people tend to say Feliz Cumpleano, without the s at the end.
Now if you are wondering why we say Felices Pascuas, here is a possible explanation.
In case you haven't noticed, there's a tiny inscription in the photo that reads Vaya Con Dios. This is the mayor's sort-of slogan which literally means Go With God.
By the way, in case you are wondering, Felices Pascuas in the Spanish speaking usually means Happy Easter.
Finally, let me take this opportunity to thank everyone who reads this blog, shares it, and most especially those who frequently comment on my articles. You are the reason why this blog exists. Felices pascuas con vosotros!