By default WP Recipe Maker adds recipe metadata to all of its recipes. According to Google’s guidelines this is only allowed for food recipes, however. We also have metadata for how-to instructions, but not everything is covered by that either.
If you want to use the plugin any of those other non-food and non-how-to recipes you need to make sure that metadata is not there by selecting “Other (no metadata)” as the recipe type when editing a recipe:
The plugin will not output any JSON-LD metadata in that case, making sure you’re in line with Google’s guidelines.