Bug: Every time keyboard restarting!

[gurunarayanancse]

otpFieldsCount is 4. I had keyboard type .alphanumeric.
Suppose I want to Enter like "231C"

1. First Input field, I change keyboard to number (enter "2")
2. while editing second input field, keyboard automatically restart from alphabet, so again I need to change keyboard to number(enter "3")
3. For third field again change to alphabet

Expected output:
Suppose previous input is number keyboard, next should not restart. again should be in same mode.