What's the story with nezirut Shimshon in hatarat nedarim?

Question

In the standard text of hatarat nedarim, Artscroll has

וכל מיני נזירות שקבלתי עלי חוץ מנזירות שמשון

Koren has

ואפילו נזירות שמשון

There are three types of nezirut (maseches Nazir 1,2): nezirut olam, nezirut Shimshon, and nezirut for a specified time period. (Nowadays the third one means "for a specified time period or until Mashiach comes, whichever is longer.)

If I had accepted any of these forms of nezirut (something I've never seriously considered and never plan to do, like 99.999% of people) and wanted to maintain it, I would explicitly exclude it myself in the hatara. I would do the same for any other vow I wanted to maintain. I assume that someone knowledgeable enough to accept nezirut Shimshon is also knowledgeable enough to change the text on the fly when necessary and not blindly follow the siddur.

Why does the standard text exclude or explicitly include nezirut Shimshon in particular but not the other forms? And where do the two versions come from?

(Actually, if it was up to me to exclude one of the three and I had to pick one, nezirut Shimshon would be my last choice. If you accepted a temporary nezirut, annulled it, and then brought the korbanot, you'd potentially be bringing chullin into the azarah, or at least an unnecessary chatat! Bad idea. Same if you accepted nezirut olam and then someone died near you. Apparently the standard text, like most of the siddur, is not Mashiach-proof, since it doesn't exclude any kind of korban vows.)

Answer 1

Rav Ovadia Yosef Zt"l summarizes the discussion around this issue in Chazon Ovadia Yamim Noraim pg 43

The main points are:

Pitchei Teshuva YD 239:6 writes that this text in hatarat nedarim is correct because a Nezirut Shimshon cannot be annulled (Gemara Makot 22a).

Some poskim (based on Leket Hakemach citing Ri Migash) defend the text by citing opinions that a Nezirut Shimshon may be annulled if one was not yet actively a Nazir Shimshon.(Such as if someone took an oath to be a Nazir Shimshon of such-and-such should happen, and that event did not happen yet).

Other poskim (Radbaz, Ralbach and Maharashdam) disagree with that notion.

Mabit writes that although Nezirut Shimshon cannot be annulled by charata and can be annulled with a petach.

A Nezirut Shimshon can be annulled if one stipulated before the vow that he reserves the right to annul it.

Since every year we make a moda'ah that annuls all our vows of the coming year, the Nezirut Shimshon does not take affect anyhow.

Answer 2

Nezirut Shimshon exists and is a nezirut.

There is the opinion of Rabbi Shimeon, following which to vow nezirut Shimshon is nothing. Gemara said, no necessarily following this last opinion, that Shimshon himself was not a Nazir because his status was dicted by an angel (for Shmuel, his pregnant mother did make a vow of nezirut following Tana kama on the last chapter of masechet Nazir)

ר"ש אומר האומר נזיר שמשון לא אמר כלום שלא מצינו שיצאת נזירות מפיו 

ושמשון לאו נזיר הוה והכתיב (שופטים יג) כי נזיר אלהים יהיה הנער מן הבטן התם מלאך

The Rambam, as reported by @double AA, has an interesting peak, he follows the Stam mishna that there is nezirut Shimshon, not by hatpasa on Shimshon, but as a kabala of different prohibitions. (explained following the Mahari Ben Lev there, quoted in kesef mishna and To. YT. mishna 1:2)