Rav Kook Ate Manischewitz Matzah
According to this (Hebrew) article from Musaf Shabbat by Rabbi Prof. Neriyah Gotel, Rav Kook was an enthusiastic consumer of machine-made Manischewitz matzah while he was in London during WW I. The article describes the different versions of a letter by Rav Kook that were published in different editions of Igrot Ha-Ra’ayah, one that includes explicit praise and description of using machine-made matzah, and the other that doesn’t seem to make much sense since it was heavily edited.
See this post by Menachem Butler for references to literature on machine-made matzah. My custom is to use machine-made shemurah matzah for the mitzvah of eating matzah at the seder whenever it is available.