It is possible for words that are used in exception events to show as missing recognition in the dashboards.
For example, your exception event might contain words such as 'Hello' or 'Hi' but they still appear in the 'Missing Words from user input recognition' widget in the Recognition Analysis dashboard.
To exclude these words from showing as missing recognition, simply add them to the stop words. Note that this solution can make it harder to identify if the event isn't working as it should.