Unexplained InflateException Claiming Invalid Column Count

When attempting to debug my app, I receive the following message:
Android.Views.InflateException: 'Binary XML file line #1 in com.companyname.spades_scorekeeper:layout/activity_main: column indices (start + span) mustn't exceed the column count. '
If I understand this message correctly, it is saying that the android:columnCount attribute of one of my GridLayout(s) is too small. As best I can tell, this is not true. Not only have I checked my code many times, but everything is displayed correctly in the designer as well. If there is a code problem, why is the designer not complaining, and how do I find it? If there is not a problem, why am I receiving the error? Thanks.
No, the ui/xml code is 100% static
Could you share a demo that could reproduce this issue?