I do have the 148th Pennsylvania losing a color on or between June 16-18th, 1864. That was a Second Corps color though.
I do have a small map on the Eastern Petersburg battles. On June 18th, 1864, (late afternoon), the 2nd Corps is on the far right of the Union line. The 9th Corps is in the middle and the 5th Corps is on the far left. Hancock's 2nd Corps would have fought, Hoke's division and Wise's Va Brigade. Burnside's 9th Corps took on Fulton's Tenn Brigade, Elliott's SC Brigade and Ransom's Brigade. The 5th Corps under Warren took on the Ransom's men fully.
My source on that information, comes from the 17th South Carolina historical book. With maps of where the 17th SC were in battles.
What we need is a regimental detailed maps on the Petersburg battles. Who was on who's left and right. That would solve many answers.
Have a good day,
Shawn