Why does physically touching a specific pin eliminate circuit issues?
Touching a pin does not eliminate the circuit issue, it just hides it. Your circuit still have an issue, and a big one - this particular CAM_DATA[7] bus signal has insufficient timing relative to bus clock, likely an insufficient hold time. A finger, or tweezers, or scope probe all do have some capacitance, 3pF, 5pF, or 10pF. Attaching a probe (or touching a pin) increases signal propagation delay (or elongates signal edge) on that particular signal, so it gets properly latched, and the overall data don't have intermittent corruption anymore. 

Actually, the fact that you have discovered this kind of sensitivity is a good sign, since it likely means that the entire bus has a serious problem that must be fixed. Under some voltage or temperature or component variation the this effect can show up on some other data line. You need to check the entire bus for violation of hold time and make sure the data-clock relationship meets specifications with some margins. If the timing is tight, it could be that the bus does not have trace length matching, or something else.

Since it looks like the bus is an input to FPGA, advancing internal clock will fix the problem - it is likely that the clock insertion delay was uncounted for relative to the data I/O cell delay.

ADDITION: After the bus timing is fixed, I would recommend a quick and dirty test: when your system is running a relevant test, firmly press a wet finger over the bus traces, and see what happens. A good high-speed bus, with typical 50-Ohm traces and solid timing will continue to function, while a marginal bus will break down and show some garbage artifacts. Just applying a finger over solder mask increases the signal propagation delay along the bus transmission line (by 50-100ps), which might cause data integrity problem on a poorly implemented bus. Of course, the "wet finger test" does not replace a thorough validation of bus margins by clock timing margining and data skew checking.

There is an excellent elaboration on the "wet finger test".