Saying the word "one" kicks one out of the form

[josemvidal]

Same thing happens if I say "five"

[tjcocklin]

The problem here is the input doesn't match any of the Intent handlers, which causes the skill to exit.

Normally the FallbackIntent is suppose to catch, and reply to any input that is not recognized by the handlers according to the docs.

That said, there are many unresolved issues surrounding the use of the FallbackIntent.

see: https://forums.developer.amazon.com/topics/fallbackintent.html