I recently updated QGIS from 2.18.1 to 2.18.2 on a Mac OS using the KyngChaos installer.
After the update, the DB Manager no longer recognizes the SpatiaLite extension on sqlite databases. The below image shows the installed libraries in QGIS.
Geometry layers appear fine in the QGIS Browser Panel. I can add these layers to the Map Canvas without problems. When I open the same database in DB Manager, I don't see the SpatiaLite, GEOS, or PROJ libraries in the "General Info" description for the database. If I try to view a spatial layer's table, I get the following error, "no such function: GeometryType."