Hi @BenevolentBowd. Thanks for noting this. We checked in with the dev team and they have verified that this is an issue. Impresario tent in Belkarth does not have Witchmother Taerma. We have this on our list of issues to fix. This should be the only place where the quest is not attainable, but if any other places pop up, please let us know.
@SammyKhajit thanks for the feedback. We checked with the team and the Witchmother’s Servent pages drop rates are working as intended. However, we will pass your overall feedback on drop rates along.