Ahhh it’s likely that the buoyancy system checks to verify it’s specifically the WaterBodyCollision channel. So if possible you may need to change the settings inside the DefaultEngine.ini inside your Project Folder/Config. Find the entry for the WaterBodyCollision, and replace it with this:
+Profiles=(Name="WaterBodyCollision",CollisionEnabled=QueryOnly,bCanModify=False,ObjectTypeName="",CustomResponses=((Channel="WorldDynamic",Response=ECR_Overlap),(Channel="Pawn",Response=ECR_Overlap),(Channel="Visibility",Response=ECR_Ignore),(Channel="Camera",Response=ECR_Ignore),(Channel="PhysicsBody",Response=ECR_Overlap),(Channel="Vehicle",Response=ECR_Overlap),(Channel="Destructible",Response=ECR_Overlap)),HelpMessage="Default Water Collision Profile (Created by Water Plugin)")