Have a look at the following post. I do not know if this is precisely the same as your issue but it seems to be in the same family.
I can confirm that the "Access Topics" privilege is not functioning correctly, so will need to look into that.
However, with "Create Topics" disabled, the "New Topic" button is not present, and the category itself is not present in the composer dropdown, so that privilege is working as intended.
Fixed in latest master, the labels were swapped, so "Access" was actually controlling "Create", and vice versa.