I just upgraded to Version 22. When I go to exit the game, and the gray box at the bottom says to press Back again to leave the game, there is some sort of formatting code on the Back that is not rendering correctly: [#!]Back[#]
If I had to hazard a guess, the two tags seem to be in the wrong order, and maybe it’s missing a color code as well.
Using Android, updated from Google Play Store.