I suppose it must have gotten really bad if it got all the way to Presbyterians.
I assume it started in the Messianic and Hebrew Roots movements, spread from there to Dispensational Evangelicalism (possibly with influence from people who visited or studied in Israel and were effected by Israeli Messianic Judaism, which celebrates the Rabbinic liturgical calendar but is often closer to American Evangelicalism than foreign Messianics), and from there somehow to some unprincipled Presbyterians.
Theologically, there are two problems here:
1. The Temple Feasts, of which Passover was one, were given until the Seed should come. They were signs and seals pointing to a future redeemer. However, the only redeemer of God's elect already came, and so we need a smaller number of simpler signs & seals pointing backwards towards the redeemer who came, died, rose, ascended and shall return to judge.
2. The Rabbinic Seder tradition has very little to do with God's original commandment. Sure, they kept the unleavened bread and bitter herbs, but there are a ton of new elements and traditions of human origin and one thing is starkly missing - the actual passover! There is no lamb for there is no temple, and the idiots who try to get sheep to the right mountain every year are arrested for bringing livestock to a mosque without permission.
We have no warrant introduce fake versions of temple feasts out of plastic and human imagination, and it doesn't matter if we call it Pesakh or Easter.