Sergeant Wilhelm August Heinrich "August" Fehlbehr, born in Bremen, Germany 15 Feb 1895, was the son of Heinrich Martin Ludwig Fehlbehr and Catherine Marie (Herbst) Fehlbehr of Brooklyn, New York.
On 6 Oct 1906 Catherine Fehlbehr returned from Bremen to New York aboard the SS Chemnitz. Her home is listed as 42 2nd Street in Hoboken. She is listed as having come to the United States in 1904. She arranged for the passage of her sons Johann and August from Bremen to New York the following April.
On 9 Apr 1907 the SS Kronprinz Wilhelm sailed from Bremen with August 11, and his brother Johann 15, arriving in Hoboken on 18 Apr 1907. Their fare was paid for by their mother Katherine Fehlbehr, already residing at 204 River Street in Hoboken. August becomes a naturalized US Citizen.
German military records in Ancestry list Wilhelm August Heinrich Felbehr, born 15 Feb 1895 in Bremen as having served in the German Army for 36 months from 1914 to 1917. There is a handwritten reference to New York in the comments. Can't read any of the other German cursive.
On his US draft registration August lists his birth date as 15 Feb 1895 in Bremen and his occupation as brakeman for the Pennsylvania Railroad.
His address is 418 Van Brunt Street in Brooklyn. August's New York Abstract of WWI Military Service says he was inducted into the US Army in New York City on 28 Sep 1917. He was promoted to Sergeant 34 days later 1 Nov 1917. Without prior military experience this would seem inordinately fast. He leaves for France 7 Apr 1918 with the 308th Infantry Regiment. The 308th is attached to the 77th Division.
So, here's the scenario shaping up: August follows his parents to America at age 11 from Bremen in 1907. War in Europe breaks out in 1914 and Germany calls her sons home to fight for the Fatherland. August, a naturalized US citizen, goes back to Germany and enlists in the German Army (US is not a combatant at this time). He serves 36 months and somehow gets out of the German army in early 1917 (possibly before the US entered the war in April) and makes his way back to New York. Because he was a US Citizen fighting in the German army the US entry into the war may have caused his dismissal from the German army. Back home he must register for the draft and is inducted into the US Army 28 Sep 1917. Because of his prior military experience, he is promoted from Private to Sergeant in 34 days from his induction. He wouldn't have finished basic training in 34 days.
Sergeant August Fehlbehr sails for France with Company I of the 308th IR from New York City aboard the SS Justicia on 7 Apr 1918. His person to contact in case of emergency is his remarried mother, now Katherine Weiss back at 418 Van Brunt Street in Brooklyn.
On 17 Aug 1918 August was severely wounded in an artillery strike just west of Fismes near the Chateau du Diable. He died of his wounds four days later on 21 Aug. 77th Division Aug 13-21 at Chateau du Diable is visible lower right on the map just south of the main road (now the N31) and north of the railroad line.

1st Sgt. August Fehlbehr, AEF SN# 1709535, Co I. 3rd Battalion, 308th U.S. Infantry Regiment, 154th Brigade, 77th Division, AEF.
Awarded the Purple Heart Medal for actions against the enemy.
WIA while serving as Co. 1st Sgt. with Co I. during an enemy artillery strike upon his Co's. position off of Route Nationale #31 near the Château du Diable, west of the French town of Fismes, France during The Defensive Sector (Vesle) on the evening of Saturday, August 17th, 1918.
DoW on the morning Wednesday, August 21st, 1918.
Upon 1st Sgt. Fehlbehr's death, 1st Sgt. Fehlbehr was initially interred at Grave #38, Temporary American Cemetery, Coincy, France on the afternoon of Thursday, August 22nd, 1918, and was finally reinterred at Grave #9, Row 14, Section B. at Oise-Aisne American Cemetery, Seringes-et-Nesles France on the afternoon of Tuesday, June 3rd, 1919.
Source: Find a Grave