I've replaced this
spritefont/runtime.js
this.type.gl_rect.set(0,0,(this.bctx.canvas.width-1)*this.scale,(this.bctx.canvas.height-1)*this.scale); // remember this uses coordinates, so width/height minus one
to this
this.type.gl_rect.set(0,0,this.bctx.canvas.width*this.scale,this.bctx.canvas.height*this.scale); // remember this uses coordinates, so width/height minus one
Error is gone. For what was -1 width/height? Will it cause to any consequences?