This morning trying to enter the data on my HTC one I could not enter the exact number (gallons, miles) due to the absence of "." on the keyboard.
HTC has just updated the phone system and I'm pretty sure it is due to that
I want to say that I have seen this issue also, after seeing several complaints on the Play Store Reviews. I have being playing with the Android/Samsung S4 keyboards and noted that the period was greyed out on the Samsung default keyboard. I changed to Jelly Bean Keyboard and the issue went away. I think that it worked on the Google keyboard as well.BTW, the phone switched back to the Samsung keyboard on its own.... Hope that helps....