I think I may have stumbled across a rendering bug that occurs when graphic objects are added as children to sprite objects.
This code:
let graphics = this.game.add.graphics();
graphics.lineStyle(2, 0x0000FF, 1);
graphics.drawRect(0, 0, 32, 32);
let sprite = this.game.add.sprite(center.x, center.y);
sprite.addChild(graphics);
this.game.add.existing(sprite);
Results in different dimensions for the sprite in (Safari / Firefox) and Chrome. Chrome reports the sprite's dimensions relative to the graphic object (32x32), however Safari and Firefox both incorrectly render the sprite's dimensions as (1x1) from a call to this.game.debug.spriteInfo().
It causes my tetris pieces to render differently in both browsers. In Safari / Firefox, I am forced to set the rectangle to the dimensions of (1x1) and use the sprite's width and height properties to set the dimensions correctly. However, this breaks the sprite in Chrome.
EDIT:
It appears the offender is this property: "sprite.texture.frame.width". In Safari it's 1 and in Chrome it's 32.