If either of those cells (C4 or C61 in your screenshot) are calculated by a formula, it is possible that the result is not exactly 1271.65. You may have the cells formatted to display two decimal places but that does not round the actual number in the cell, it just shows it that way. If you use ROUND in the formula it will round the number.
=ROUND(your_formula, 2)
Alternatively, you could do "Text is" instead of "equals" as the conditional highlight rule.
Note that 1271.654 (which rounds to 1271.65) and 1271.646 (which also rounds to 1271.65) will be the same for this highlighting rule.
You will have to decide which is better for your data and the highlighting rule. Do you want/need the values to be the exact results of the math being done (but shown with two decimal places) or do you want them rounded to the two decimal places? Your decision.