Depending on your Jira settings, your issues may have multiple fields filled out. Each of those fields can be used for sync with a sub-Box. Potentially, an issue can have multiple fields filled out. This can become a problem, if multiple different fields are used for sync - there can be two conflicting rules. Remember, an issue cannot be simultaneously assigned to two sub-Boxes. 

For example:

First sub-Box (PI1) is synchronized with 'Change risk' field (value = Low)

Second sub-Box (PI2) is synchronized with 'Risk probability' field (value = Medium) 

In Jira, there is no problem. However, if an issue meets both of those conditions (has both fields filled out as shown above), the App would have to try to move put it in both Boxes at the same time, which can't be done.