Why was he born THERE?

Sometimes you come across a surprising fact, a fact that doesn't fit anything else you know; and then you start to wonder what it means.  When I started researching genealogy, I assumed my great-grandfather Gerhard T. Siemens #6463 (1834-1908) was born in Rosenort, Molotschna, South Russia.  His grandfather Klaas Johann Siemens #46557 had settled farm #14 in Rosenort when it was founded in 1803, and the 1835 census recorded little Gerhard as living there as a one-year-old child with his parents, grandmother, and other family members.  It only made sense that the family had lived there continuously from 1803 to 1835, so of course my great-grandfather was born there in 1834.

Here's the 1835 census of Rosenort farm #14 so that you can see for yourself how logical my assumption was:

Katerina Simens" household, 4 February 1835, 8th Revision of Census of Russian Empire, Rosenort village, Molochanskii Mennonistskii Okrug, Melitopol'skii Uezd, Tavricheskaia Guberniia, household #14.  Found in Odessa Region State Archives, Odessa, Ukraine, Peter J. Braun Collection, Fond 89, Inventory 1, File 357, p. 263R-264.  Accessed on microfilm from California Mennonite Historical Society, Fresno, California.

I underlined the one-year-old Gerhard T. Siemens in red, his 29-year-old father Gerhard Klaas Siemens is listed just above him, and his late grandfather Klaas Johann Siemens is on the first line.

So I was very surprised when I found his obituary, and it said that he was born in Neuendorf, Khortitsa, South Russia.  But the obituary was written by my great-uncle Abraham K. Siemens, and I have come to recognize him as an interested and careful genealogist, so I trusted his information.  Here is a snippet from the obituary:

Letter to editor from A. R. Siemens [Abraham K. Siemens], Die Mennonitische Rundschau, Scottsdale, Pennsylvania, 9 December 1908, p. 12 from microfilm at Mennonite Library and Archives, Bethel College, North Newton, Kansas.

The phrase I underlined translates as, "was born in Neuendorf, the Old Colony, South Russia."  Khortitsa was called the "Old Colony" because it was settled first.

I have searched all the online records for Khortitsa, trying to find a connection, but I found no Siemens there who were related.  I don't know where his mother, Gertruda Thiessen, comes from; so I searched for her in Khortitsa without success.  I didn't know what else to try, but this has really bugged me for a long time.  Why would a boy be born in Khortitsa when his parents and grandparents always lived in Molotschna and even had a farm there?

I still don't have the answer, but I noticed a new bit of information today.  The online version of Grandma says that his aunt Helena Siemens #3759 was married in Einlage, Khortitsa, on 19 August 1830, to Abraham Johann Friesen #3751.  Since Mennonites were traditionally married in the home of the bride's parents, this would mean that little Gerhard's grandparents were living there in 1830.  Did they live in Khortitsa from at least 1830 to 1834?

I've looked for Gerhard's parents and grandfather Siemens in Khortitsa without success, but what if it was his grandmother Katharina (Friesen) Siemens #46558 who had relatives in Khortitsa?  What if they moved to Khortitsa to live with relatives when they retired from farming?  They could have still been officially registered at their farm in Rosenort, Molotschna, but actually been living in Khortitsa.  There are three Friesen families listed in the May 1814 census of Khortitsa, so I wonder if they might have been relatives of little Gerhard's grandmother Katharina (Friesen) Siemens.  And one of them, Cornelius Friesen #198463 came from the same Heubuden church in West Prussia that Katharina Friesen came from. It's an avenue for further research.