Early maariv on 2nd day Yom Tov

Question

A shul in my city made an early maariv for the 2nd day of yom tov. Knowing who the Rabbi is, he did not do this out of ignorance. There are 2 issues I am unclear about:

1. Are there contemporary sources that allow switching your mincha-maariv cutoff even in the absence of adding kedusha (Tosefes). (This would be less of an issu if the 2nd day were shabbos or early maariv on the first day if you hold there is a mitzva of tosefes for yom tom)

2. How does this circumvent the hachana issue. Granted you accepted the 2nd day, but that shouldn't negate the first day in terms of melacha, especially since they are 2 kedushas.

Any insight?

Answer 1

After asking a local poseik who is a famous expert in the halachos of Yomtov Sheini regarding this issue, these are some of his comments:

1. If the minha is davened before plag then a lack of tosefes kedushas hayom is not a problematic factor.

2. It does not negate the first day in terms of melacha and therefore it can lead to many michsholim (errors) regarding hachanah and melachos di'oraisa and therefore it should not be done.