Label Missing on Multi-Line chart when using Fire Fox browser

[dpierucci]

When I create the following visualization using the syntax and data provided one of the point labels is missing when rendered in Fire Fox. All labels are visible when rendered in Safari.

Syntax:
line x(Model) y(Error) color(K) legends( none ) interaction(none) + point x(Model) y(Error) color(K) label(Feature) legends( none ) axes(x:3 :'"MODEL"':grid, y:'"ERROR"':grid)

Data:
Model,Feature,K,Error
M1,Sex,K3,0.25
M2,Drug,K3,0.5
M3,BP,K3,0.75
M1,NA,K4,0.95
M2,K,K4,0.65
M3,Drug,K4,0.85