This problem is not limited to the iOs, also have the same problem on Android 4.0.3 platform.
According to ASUS support, TF101 tops out at Android 4.0.3. Hoepfully, development can fix this bug for the signs so I can use it.
Same issue on ASUS TF100 running Android 4.0.3 when entering text on signs. No updates available.
Brian Hill
This problem is not limited to the iOs, also have the same problem on Android 4.0.3 platform.