This is new to me on the 1st Minnesota losing a flag to the 3rd Tennessee PA. You just found a hell of a find! I remember awhile ago Gregg Biggs posted a list of flags captured at 1st Bull Run.
The 1st Michigan Infantry lost their regimental flag to the 27th Virginia. *OR 2, series 1, page 495.*
The 4th Virginia captured a artillery flag, Griffin's?? *OR 2, series 1, page 482.*
Radford's cavalry (6 companies) captured the "69th New York Militia's" "colors". Very difficult to find if one flag was captured or two/both. *OR 2, series 1, page 497*
OR 2, series 1, page 527. "Among the trophies taken by my regiment was the flag of the 1st Regiment, 2nd Brigade, Fourth Division, of the State of Maine, with it's proud motto, "Dirigo," and a small Federal ensign." Colonel Kershaw, 2nd South Carolina.
Now the "4th Division" was not engaged and no regiment in the 4th Division was from Maine. 1st New Jersey Brigade: 1st-2nd-3rd-4th New Jersey (3 months) and 2nd Brigade: 1st-2nd-3rd New Jersey and the 41st New York (3 years).
Now, the 2nd Maine's colors were regained, and the only other Maine regiments at 1st Bull Run (and in reserve) were in Howard's brigade (3rd Maine, 4th Maine and the 5th Maine). One of those regiments lost a flag to the 2nd South Carolina.
OR 2, series 1, page 477 "28 pieces of artillery, 5,000 muskets, a garrison flag, and ten colors were captured on the field or in the pursuit."
OR 2, series 1, page 428 "8th New York brought in safety two Union colors left behind by soldiers on the field of battle." *OR 2, series 1, page 357*. "The beautiful California stand of colors presented to the regiment that day before by the ladies of San Francisco formerly residents of Maine. The colors were lost, but regained. C.D Jameson, Colonel Second Regiment Maine Volunteers."
OR 2, series 1, page 503 "Some nine regimental and garrison flags." Beauregard had wrote.
OR 2, series 1, page 573 "Colonel Terry shot down the United States flag on the Fairfax Court House. Another was taken from the court-house, and the third one, to which you probably refer, was taken from some soldier by Private R. L. Davies, of my company, who had it in a haversack--no doubt to be raised on the first captured battery taken. It had no staff, but was carried carefully wrapped in the haversack." Captain Edgar Whitehead, Company E, Radford's Rangers.
Union regiments I question that may have lost a flag.
5th Maine: 333 missing/captured plus 2 officers. This regiment was on the extreme right of the Union line.
4th Maine: 119 missing/captured plus 2 officers.
2nd Vermont: 91 missing/captured plus 1 officer.
From the book "Battle at Bull Run" by William C. Davis, page 248 "But even here it was Kershaw who, on his own, extended the Confederate left to blunt Howard."
Well, I think the 5th Maine lost a flag to the 2nd Maine. The fun part is trying to prove it.
Thank you all for the help! We will figure this out!
Have a great morning!