Greetings - I can only assume you're using the mobile version. In any case, I just downloaded the Crisp Grain Add-On and looked at the Maris Oter and the ingredient seems to be fine. Then I went and added the ingredient to a recipe and after the ingredient was selected a dialog box came up allowing me to edit the properties. The dialog also allowed me to select Add After Boil. I'm wondering if perhaps that option was inadvertently selected while you were adding the ingredient.
Hope this helps.