Well, my assumption is that the underlying library has some issue with changing the columns while data is loaded. It’s not great fun, but when using open source you sometimes have these limitations or bugs that need to be sorted out upstream. Even if you build a pull request, you often don’t want to deploy it until it’s been accepted and merged for fear that it may not be in the next version you try to move to.
It looks like this particular issue is due to DataTables requiring that the entire table be destroyed and reinitialized when you want to add or remove columns and would not be an insignificant amount of work to fix because they likely cache all sorts of values that are calculated on init that are not recalculated.
EDIT
For reference: how to refresh table after adding columns — DataTables forums