Steps to reproduce:
1. Start scheduling a capture, and finish off the Source page but do not click Next
2. Reselect one of the dropdown fields (ie, if the duration hour value was 01, select it again)
Your field's value advances by one (1 hour becomes 2, etc). This is not reflected in the UI, which still shows the correct, but the scheduled values are incorrect - as shown in the Summary screen. Setting the field to the same value again does nothing - it does not retrigger the event validation code as it previously did. Setting the field to another value works as expected, and will allow you to set it back to the original value correctly as well.
The field should be set to the correct value.
Workaround (if any):
If this behaviour is triggered it can be cleared by refreshing the page, or setting the field to an alternate value before setting it to the correct value. For example, change the duration to 3 hours, then back to 1 hour.
Raising to RB per discussion in dev meeting 2016-09-13