Authenticity of the Zohar
While Kabbalah seems a shunned topic in contemporary German Orthodoxy, we know of course that R' Yaakov Emden and R' Yonason Eibetshitz were kabbalists (as well as Talmudists) and of course the Chisdei Ashkenaz knew kabbalah. But how much of the Zohar is authentic kabbalah. This is a long standing debate. Both Yaakov Emden and the Chasom Sofer believed that only part of the Zohar was authentic. The articles linked above takes us through arguments for and against.