Table 5 and 6 on page 8 of the MAX7219 data sheet. Table 6 shows the bit assignments to the seven segment structure. Decimal point is bit 7, segment A (top bar) is bit 6, continue clockwise to segment F (top left) - bit 1, finally the center bar, segment G, is bit 0.
That would make the code for digit 2 0x6D.
Are you using one of those 8 digit display modules mounted with the MAX7219 from eBay or Amazon or your own build?