There are a couple of possibilities.
Most likely -- Check your rear cable for "extra length" If you loosen the rear cable nuts, this will allow the drums to tilt forward slightly, making a shorter path for the front cable. It's like robbing Peter to pay Paul in a way. Sounds like someone did some work on your Drive and over-cinched the rear cable.
Least likely -- Someone incorrectly replaced a V-2 cable with a shorter V-1 cable. This would have entailed drilling out the cable slots in the drums to accommodate the older cable.
BTW, after you get this fixed, remember the order of tensioning the cables is idler first, then front sprocket and finally, rear sprocket. Cable "squeeze" flex should be
approximately 1/8", 1/8" and 3 /16" respectively.