I don't think they ever said when it would be back until very recently, either. All that we knew was that it would be back at some point over the next year or so. Of course it makes me wonder because in the preview Kenzi has blonde hair now, which is what Ksenia is having her hair recently with her other projects that she's been in, so I'm assuming that after she left early S5 they waited so she could return to film the rest of the season with her? Maybe? Idk.