Empty groups shown when blocked entries are hidden from org-agenda

When using `org-enforce-todo-dependencies` setting to hide blocked entries from the regular `org-agenda` Empty groups (which otherwise would contain the blocked entries) are shown for today.

Empty groups for the following days are hidden alright, unlike the non-hiding today's empty groups.

What could be the problem?

Where does the code decide whether to display empty groups?

Note: I am using additional custom function in the `org-blocker-hook` for some extra blocking - could that be a problem? The hook is set before `org-super-agenda` is loaded though.