I'm not sure if anyone has noticed it already but when I filter out a translation group at a novel and then go to last bookmarked chapter then that translation group has been added again. Reversely when I first go to bookmarked chapter and then filter out the translation group I get sent to the latest published chapter.
the filter is not meant to be permanent. rather, it was meant to reload the novel page while hiding (temporarily) the filtered group(s). the same goes for the other button. when you click to 'show bookmarked chapter', the page ditch the group filter and reload itself to show the bookmarked instead. the reverse is also true to this behavior. therefore, rather than a bug, i'd say probably none of the button was ever configured to overlap each other's function. they're independent, hence you did not get a combined result. however, this should be a good suggestion for improvement on the behavior of the button, imho.
Is there a rainbow outside? It's so rare to have a certain snake supporting a feature request....good job @Lucaria