Having a similar problem. I think it's to do with this issue: github.com/Scirra/Construct-3-bugs/issues/5331
Use a spritefont instead of the text object.
From the manual: "if... you wish to translate the game in future, then Text objects are probably more suitable."
I'm trying to paste text to the screen using drawing canvas to split it into pages and I'm finding this blurring effect very frustrating.