The 900 man, 1st Maine HA, had charge from Prince George Court House into the cleared field near Hare House Hill. In 30 mins they lost 632 men. (Source: Nah Andre Trudeau, The Last Citadel, Page 54.)
On June 22nd, 1864, MG. Mahone had launched a flank attack, along with Wilcox's men. They captured about eight flags. 15th Mass, 19th Mass, 42nd New York, others I will have to look up. It is possible the 1st Maine HA lost a flag there. Birney's division lost about 1,700 prisoners. The 116th PA, 11th NJ, 152nd NY are also possibilities. All regiments in Barlow's and Mott's division are possibles.
Barlow was hit first, then Mott' division.
The very next day (June 23rd, 1864), two Vermont brigades were cut off (4th VT and 11th VT.) Around 400 men from both regiments were captured. The 4th VT claimed it lost no flags. The 11th VT??
Welcome to my fun world, lol
Have a good night, Ed
Shawn Prouty