The Clutch Pedal spot welds have come loose on the car. You can verify this by looking under the plastic shield where you windshield wipers are, on the driver's side. You can see small spot welds that have come undone from the firewall. You can also hear a distinctive popping noise every time you operate the clutch pedal.

Subaru originally gave an extended warranty to vehicles that were affected by this problem, however, my WRX still was not capable of having it serviced. It will cost approx. $2,000 for the dealership to handle just simple spot welds because it requires taking the entire dash out of the car and re-positioning the pedal bracket.

This is a dangerous issue, and though uncommon, can lead to the pedal coming completely off the firewall and leaving the transmission inoperable beyond the gear you had it in.

I am going to soon have it fixed by a Subaru Specialist, not a dealer, and have read it is recommended to add a clutch master cylinder brace to help prevent further movement and reinforce the firewall from flex, which all of this can cause unintended clutch wear and malfunctions over time. You can also opt for using bolts instead of welds to secure the bracket, but will require drilling and some fabrication.