Why eat gebrochts on the 8th day?

Question

Apparently, among those who don't eat gebrochts during Pesach, the custom is to specifically eat it on the 8th day. From http://www.chabad.org/holidays/passover/pesach_cdo/aid/265990/jewish/Gebrokts-Wetted-Matzah.htm:

On the eighth day of Passover, which exists only outside the Land of Israel, the gebrokts stringency doesn’t apply, and all feast on matzah balls and matzah brei, and dip their matzah into soups and salads. In fact, many have the custom to try to eat their matzah with as many liquids and wet foods as possible.3

The simple reason for this is that the celebration of the eighth day is of rabbinic origin.

So what? I've learned, and Wikipedia agrees, that the second day of Yom Tov is just as strict as the first.

If the reason for the custom is that we are concerned that the matza isn't fully kneaded and can become chametz upon contact with water, why are we not concerned on the eighth day?

I am interested more in answers based in halacha than chassidic ideas.

Answer 1

Does chabad eat gebrochts? I point out that because this is a rabbinic prohibition and a minhag of stringency, the last day of Pesach is used to show that it is not a full prohibition of Chametz. There is also a spiritual meaning to this. It appears that the eating the gebruchts in Chutz La'aretz is the significant point because the last day of Pesach is Yom Tov Sheni shel galyus. On the other hand, since the last (seventh) day in Eretz Yisrael is aYom Tov from the torah, then the leniency does not apply. Since I am only quoting chabad and do not have this minhag, then I cannot go any further than I have quoted.

I have sen that some people have eaten gebrochts on the last day in order to show that it is a minhag, however, since those cited were in chutz la'aretz at the time, I cannot say what they would have done inside Eretz Yisael.

The Vilna Gaon held that gebrochts is a minhag shtus and would dip matza in water to show that. However, any connection with the last day of Pesach is cited in error.

The simple reason for this is that the celebration of the eighth day is of rabbinic origin.

But there is also a spiritual reason given for eating gebrokts on the eighth day:

The last day of Passover is connected with the future redemption (see Remembering the Future), a time when no evil will befall us. We reflect this reality by going out of our way to eat gebrokts on this day, without fear that the matzah may become chametz.

Talk by the Lubavitcher Rebbe, of righteous memory, Acharon Shel Pesach 5744.