Bug with signs not showing up

So it started with update 10.5 and after that i figured it would go away but after the release of update 11 i knew somthing was wron that is why i am writing this report.
So I would write the sign but when i am done and i look at it no text shows up. When i try to write a sign sometimes my whole kindle will crash i just thought i would write it thanks for your time.