Problems with refreshAll of AbstractBackEndDataProvider

Hi everyone!
I developed a project with Vaadin 8 where I invoke the refreshAll method of an instance of AbstractBackEndDataProvider. This DataProvider belongs to several Grids and everything works fine: it fetches the data from db and I can see them inside the grids.
Now, I am currently dealing with porting this project to Vaadin 12 and the above-described mechanism does not work anymore: dataprovider does not fetch the data from db anymore (as seen by the debug messages of the db libraries and confirmed by java debug). To get further insight into this, I added the following :

grid.getDataProvider().addDataProviderListener(e-> {

});

When the refreshAll method is invoked I do see the debug message.

Coming to my question, does the refreshAll of AbstractBackEndDataProvider imply a fetchFromBackEnd invocation?
Any suggestion is welcomed !

All the best.

Dear all,
my mistake. The refreshAll invocation is in a UI.access(…) block, but there were still some imports to old v8 classes (for example the @Push annotation). Fixing the imports fixed the issue.
I think I need to double-check all imports in my project.
Sorry for wasting your time.
Thanks.