Screen Icons sometimes get blurred when there's text on them

[AgustinVallejo]

Recently we noticed that a couple of screen icons for Keplers Laws look blurred on certain screens:

Specifically Third Law and Lab. I removed the text (timer readout that says 0:00) and it didn't happen anymore. If I zoom in it's also not showing.

@pixelzoom suggested adding a Text option renderer: 'canvas' and it seemed to disable the blurryness but the text would not be readable anymore, so it's more like a hint towards the problem instead of a solution.