Since both my Nexus 7 and 10 updated to Lollipop the Kindle app crashes. On some books when I select "droid serif" as font it is all messed up on some books, and some will simply crash the app. When it is all messed up there is no line spacing - everything is printed ontop of each other (unreadable). All other fonts work fine without crashing.
On Nexus 10: Kindle app v. 4.7.2.11 (tablet version), Android 5.0
One book, for example, that will crash every time droid serif is selected:
Quantum Lens
I have not found a way to change the font back without opening another book that doesn't crash and change the font there. Also not sure if the phone version of the app crashes as well - none of our phones got Lollipop yet.
Update: reinstalling the app worked to fix this problem - now all works fine and I can use "droid serif" again.